What's the best pick for my first welder?

BUY A GAS setup and you can yank the liner and use flux core wire if you want. For certain get a supported brand name, one that A LOCAL WELDING SUPPLY supports

Buy one big enough you can do welding on stuff like beefing your LCA, welding perches on axles, etc. This means a 240V, 180A class machine. Many guys have bought the newer "dual voltage" 120/240V machines. I can see those would be VERY handy

My first machine was a Lincoln "weldpack" 120V machine with gas. I later bought a larger 240V 180A. Use them both. Sometimes the little one is just "handier"

You an save a lot on gas for practice and general work. I use straight CO2. It's really cheap (it's a liquid) and lasts a long time.