I'm also a long time MTG player, hi! The cost for 1000 power is less than that of a new commander deck so cheap in comparison to many games including MTG. Sometimes I don't have anyone to play MTG with IRL, and I'd rather play Splinterlands than MTG Arena because SL is play to earn and Arena is a $ sink. I like the fact that with SL I get to build my collection and buy / sell at whatever price I want all in one easy program, saves me more time than stalking deals on TCGplayer haha.
You sort of "get a starter deck" in the fact that they give you those phantom cards. I believe I also read that come Chaos Legion you'll have access to every common and rare from CL in that same way. Easiest way to get out of bronze would probably be to rent a few cards that will boost your power. There are some for rent that I don't even understand why they're there they're so cheap.
Anyways, as 1 magic player to another have fun! It's rewarding to see your collection grow just like in mtg.
Side note: In Splinterlands you can't get turn 3 Prossh Food Chain combo or Jace / Tainted Pact win, but the closest you'll get would be to own a Yodin Zaku. I HATE that guy lol!! ;)