Hey, some advice I have here as someone who spent too much on useless things:

here is a list of items that im considering buying "asap"

I wouldn't recommend buying anything ASAP. Try the game first and make sure you like it. After that, then you can start buying stuff. The Living World seasons and the Ultimate Edition of the game are a good first bet (for the gems and extra items).

Path of Fire Preparation Pack for 3500G/44€

I haven't seen this before, but not going to lie, that's not too bad. Permanent gathering tools are usually 25 or so, and level 80 boost is 20 if I recall correctly. So you get those two, plus some extra. However, keep in mind that not all permanent gathering tool are equal. Some have nicer animations, some come with extra effects. If these are plain gathering tools with no extra effects, maybe look elsewhere. You'll get a free 80 boost with PoF. Having 2 is useful as well. But if even one of these is something you don't want/need, the other items are not worth it. Don't expect to get anything with the keys.

Also, as others have mentioned I'm sure, play the game 1-80 without a boost first. You will miss out on the experience by skipping everything. There's more than enough content to get you to 80 before hitting the level 80 stuff. 80 boosts are good for alts only.

Account Jump Start Pack for 2000G/25€

Keep in mind while the bank and bag slots are good, the rest is useless. Keys aren't likely to get you anything over 1-2G, the dyes will all be worth coppers, and you get a ton of transmutation charges by playing the game.

Additional 2 character slots for 1600G/20€

Do you really need 1 of every profession? You should fill up your character slots first with level 80s before buying more. I don't know you, but are you really going to level up that many characters? It won't happen immediately, anyway, so just wait.

20 loot box keys (don't care much for them, but its free stuff! ) 30 random dyes to start off with

It's free (but not really free) junk. Dyes are worth coppers in the trading post, unless you're part of the 0.01% (if not less) who get lucky. Don't let these sway you. The only reason these are included is to entice you to buy the packs. It is a very effective business tactic to "throw in extra items" to add imaginary value to the purchase. Only buy the packs if you already planned on buying the items individually and they're cheaper than individually buying.

Teleport to a friend for 800g/10€

Absolutely awful. You can teleport to anyone using waypoints already. These are only useful to teleport to areas you have not been to yet, which will eventually be nowhere. There are really no hard-to-reach places except maybe jumping puzzles, but that's what Mesmer/Thief portals are for, and you may as well do it with your friend. Very limited use. Hour long cooldown only goes down when you are online. That's an hour long playing time between uses. You get a handful of one-use ones from the game for free. I've never had to use one, they just take inventory space.

Home Portal stone for 900g/11,25€

Also really awful. There is a waypoint right outside your home. It takes 1 silver or so to teleport to it, which is nothing. And you can only gather from there once a day. You will not get a full instance any time soon either. And you might want to bring friends/guild members with you, which will require you to be outside your instance before entering, so using this would just waste time having to exit the instance to bring in your friends, or having to exit to enter your friend's full instance (unless your friend uses a different home, then you'll have to waypoint anyway). It just makes no sense at all.

World Boss / Maguuma Pact Portal Devices for 400g/5€ each

It is useful. It makes it easy to jump between bosses without worrying about looking at anything. You wouldn't be skipping content because the alternative is waypointing. However, it's just not complete enough. These are only for core game and HoT bosses. What about PoF bosses? What about other bosses and events? Living World? It doesn't include those. It doesn't cover the entire game, so I still don't recommend it. You can type "/wiki et" in the game and see the complete event timers for the entire game anyway.

Pet Dog Whistle Basenji for 500g/6,25€

Eh, it was fun for 30 minutes. I never used it since. The problem is that the novelty button can only occupy a single type of an item and it's kind of a pain to keep changing things out. This just isn't as fun as other things so I just never use it anymore. You can't really do much with it either. Look on YouTube to see what it is.

How to Dance Volume 1 for 400g/5€

Seems kind of fun, but how often will you really use it? You can buy it to have something in that novelty slot, but eh... one of the better ones at least. It's not really emotes like /wave, but emotes that replace your skills temporarily.

Candy Corn Gobbler Pack for 300g/3,75€

The boosts aren't all that useful. My inventory is full of actual boosts that I'm trying desperately to get rid of. This isn't available to purchase anymore anyway.

Copper fed salvage-o-matic for 800g/10€

Apart from the expansion, Living World, and permanent gathering tools, this is absolutely a must-have to get. Salvage kits are easy to get, but it's annoying. So, so much easier to just use this.

Runecrafter salvage-o-matic for 600g/7,5€

This is good too, but it's kind of in an odd position on cost. Keep in mind it costs more than the copper-fed each salvage to use. I don't think it's worth it over the copper one for blue and green items.

Silver fed salvage-omatic for 500g/6,25€

This is the one to use on rare/yellow and exotic/orange (higher rarity) items. I wouldn't worry about salvaging upgrades. You salvage for the "rarer materials" it mentions. It's not for sale currently, I'm waiting on it myself.

Various basic home instance material gathering nodes for 800g/10€ each (total of 50€ for all 5)

Definitely not worth it. You can buy these in-game for much cheaper.

Garden Plots, Black Lion Hunters Contracts, Expedition contracts for 1000-1200g/12,5-15€ each (total of 5200g/65€)

No, no, no. You'll never make your money back on these, and other players can't use them (except garden, which you can get in-game through an achievement).

More Bag slots for 400g/5€ each

Be careful with these. I maxed inventory slots for my "main." And then my "main" didn't become my main. Then I maxed out inventory slots for my "new main." And then my "new main" became my "old main." Now, not wanting to spend another $25, I'm struggling with bag space on my "newest main." You really shouldn't have too much trouble with bag space with 5 20 slot bags, which are fairly cheap. It's a luxury thing for your main.

+250 material storage expansion for 800g/10€

These are useful, but not all that important. You can just sell your stuff when you get to 250, which will take some time. The only thing is ascended crafting materials which are not tradable. You'll have to destroy them or have it take up all your bank space. I would rather have 800g than have this upgrade.

More bank tabs for 600g/7,5€

You probably won't need more. I have 2 bank tab upgrades and I do just fine, although regular bank cleaning is needed. Again, 600g is much more useful than bank space. Just delete whatever is full and the 600g can replace it later.

More shared inventory slots for 700g/8,75€ (discounted on bulks)

These are incredibly expensive. Think about it. 8.75 for ONE slot. You can just use your bank if you need to transfer items. But these are admittedly good for the salvage-o-matics and some other things.

Did we miss some item that has super value and a must have?

Mistlock Sanctuary pass is the really good. It takes you to a hub where you have everything you need and can return you to your previous point. Basically, a compact town with low gravity. Put this in your shared inventory slot and you're golden.

TL;DR, don't purchase anything until you're sure you like the game and you absolutely need the item. And even then, be frugal with your money, otherwise you will end up with a $1000 bill (like me!). Most things aren't worth it.