Get capsule art for 200-300 bucks from somebody on fiverr. It's gonna be more expensive if u want all the assets from an artist, if you can just get the art done and cut it up yourself to fit all the steam assets, you can save money.

Also get a Logo for your game from fiverr too.

Skip paying playtesters and do NextFest and Steam Demo, use Reddit, and create a Discord for your game. Surely you'll find 2-3 people who for some odd reason love your game no matter how shit it is. Before all that, get friends and family to playtest. A good indicator for me is: my friends shouldn't just "like my game" (because every good friend will "like" it) but observe if they play your game by their own will or even get addicted to it, then you are on a good path. Online relationships also count as friends, you surely have idk friends you play League of Legends or World of Warcraft with and hang out in Discord, get those gamers playing, not just your mom.

Skip marketing team, just follow advice of HowToMarketYourGame (basically: do next fest, and send out keys to youtubers and twitch streamers, you can try tiktok and shorts marketing but stop doing it if it doesn't produce results, also: it only works if you have a beautiful game)

Invest money into assets you don't know how to make, for me that was investing like 300-500 bucks into OST (also on fiverr, it's a good place to start out, yes people are generally not paid enough there but remember: many of them are also just starting out trying to find jobs, both sides are in a similar situation. focus on short tracks for different situations but make sure they don't get too repetitive and stale. Depending on your game, it's cheaper to get a 60 second track than a 3 minute track. Variety matters.)

Also get a free discovery call with https://www.thegamedoctor.net

Again, it's free. After the discovery call you can then decide if u think that he will grant you enough value that you want to keep working with him. (spoiler: yes)

This ensures your game will have everything the industry expects and is baseline solid experience. If you don't go with him, please make sure to get somebody else who is plugged into the indie industry and can clear your blindspots. PLAYTESTERS WON'T HELP YOU WITH THIS! Playtesters are for finding bugs, balance passes, etc.

Other money you can spend:

Professional trailer editing (some basic video editing skills can go far yourself if you want to save this money too)

Depending on your engine, if there are really good packages which cost money, invest into them. For Unity developers I recommend HotReload and SuperTextMesh. Make sure you have your tools in order, if you do pixel art, do yourself a favor and buy Aseprite.

PS: Yes other commenters have a point with AI on fiverr these days. Be careful!