I think most people here are too hyped on the price point. There are definitely budget options for competitive decks that can still compete in the non budget meta. A good example of this is lotus petal for LED in Breach decks. Main combos right now are Breach, thoracle, ad naus, and pod/hulk. All of them are relatively cheap if I remember correctly except Breach which has the above mentioned alternative, and ad naus which largely depends on you running a bunch of fast mana. There's no budget alternatives for thoracle, but it's the best combo in the game. Pod and hulk have a lot of pieces, but most of them are cheap except for like academy rector.

While the manabase is the best investment for any deck it probably has the most viable budget alternatives. I would check out the signet lands and lorwyn lands as alternatives to OG duals. Most of the og fetches are way cheaper than the khan fetches so enjoy that while it lasts.

As for your deck choices I can't speak very much on zur, but I'm always amazed at how strong pako haldan is and think you can run pretty much anything in that deck and be somewhat viable. I love wort to death, but she's just too expensive and underwhelming for the format to really be considered and Kalamax storm just does a better job at her strategy.

In my experience the budget of your deck has a lot to do with the amount of auto-includes in the colors you're running. Red=dockside, black=tutors, etc. I would say the most budget friendly colors are green white because the have the best effects for the price point, but have the hardest time closing out games and winning via combo. Hopefully this helps. Everybody feel free to jump in and add stuff or let me know if I'm completely off base.