Starting in Commander with Simic or Temur

Hi! I've been playing Magic with my friends for quite some time now, but had a break from it since Streets of New Capenna came out. I never had a perfectly structured deck whatsoever, playing with cards I pulled from packs mostly just for fun. The guys made more competitive decks and I found myself losing with the rather random cards I got in my deck. Now I want to get myself into Commander more deeply, and as I enjoyed Simic decks the most, I was looking into getting a relatively cheap and structured deck with a Commander like Grolnok, the Omnivore or The Goose Mother. I'm interested in Temur also, but that's second. I'd love to get some tips on how and with what to build my first "serious" Commander Deck and some strong other Commanders I could play. Note: I'm a broke student and can't afford no big pricey cards :)