OP, for the $75 bucks you have into that machine you aren't doing too bad. Just use that to practice. Buy some metal and start working pieces together using different welds. Try different current/speed adjustments to see what the welder does. Try different techniques. Push/pull. up/down etc. If you find yourself in a good spot and want to get deeper into welding, fork out the $500-$2000 for a really nice machine and you will be able to *safely* weld frames or heavy gauge steel. I wanted a Miller 211 but I found my Lincoln 180 for a killer deal. I got the welder (and attaching parts) welding helmet, cart, tank, crate of wire, aluminum spool gun plus some extra consumables for about $550 (very) lightly used.
I bought a tank of Argon and now I can weld aluminum too (not the best or prettiest), Im now casually looking for a TIG.