Mig will give you the best mix.
Tig has a high learning curve and needs expensive tips and gas. Stick really doesn't work will with thin sheet but will work on rusty/thick steel.
FCAW on a 110V unit can do 1/2in steel.
GMAW can so 20 gauge with clean beads.
OA can cut, and do thin metal, but acetylene is expensive and you gotta learn how to work the weld puddle.. and overhead beads with OA are not for beginners.
FCAW Mig needs no gas and go thick (like Stick)
GMAW needs gas but can go thin (like Tig) and is MUCH faster.
Last is cost:
Stick welder: $300 or so.
MIG: $300 or so
TiG: not less than $500-1000
OA: $100 for a HF set (yes, they are highly rated and even my local welding supply recommended them) but you'll need tanks. If you buy tanks add about $400-600 for a 240cu/ft O2 and 80Cu/ft Acetylene
