Those of us who have welded for decades cringe at these comments. Yes a mig is easy to use but it is also easy to make some pretty welds that have no penetration or strength.
Cringe all you want... That aux battery tray was my very first welding project over 17 years ago. It is still in my Ranger today carrying around a big 65-lb #27 deep-cycle battery trouble-free.
I would certainly add though that you definitely should start first with non-critical projects such as the tray above, bumpers, rocksliders, etc. Once you've gotten a good handle on your welding skill after these items,
then you can start going for the bigger more critical stuff.
Welding isn't something I will be doing haha, Its one of those I would rather someone else do it... I know wimpy way out but I accept the fact I don't know how and don't have alot of time to learn .. lol
Please don't let posts like that intimidate you, a MIG machine is quite easy to use. Like anything, some practice will be needed in the beginning, but you should have it down pretty quickly if you're fairly adept at learning (like I said, it took me maybe 20 minutes to get comfortable enough to start with my battery tray project).
My suggestion is to start with reading a good book on welding such as this
Haynes Techbook. It shows you all the ins & outs, what good & bad welds look like (and what is needed to make the bad ones better), explains what all the different processes are (and the advantages & disadvantages of each), terminology, and so on & so forth.
As for welders, a 220V machine certainly is best if you plan to weld on structural items such as suspensions and axle brackets, but a GOOD 110V unit can easily handle building of bumpers, skidplates, headache racks, tire/jerry can mounts, RTT mounts, and the like.
Depending on how much you want to do, either one of these can be a good choice:
http://www.amazon.com/Hobart-500559-Handler-Wire-Welder/dp/B009X43F38
http://www.amazon.com/Hobart-500554-Handler-Wire-Welder/dp/B005CNOVZU
A welder is not something to use exclusively for your vehicle either, I've found dozens upon dozens of uses for it around the house too (repairing a wrought-iron gate or railing, making a bracket to mount a solar panel for a string of LED yard lights, to even building a wheelbase extender bracket for my E-Maxx R/C car are just a few examples). You mentioned some of your wheeling buddies were familiar with welding, they should be able to guide you along and have you up and running in no time if you truly have an interest in making your own accessories.
Mine has paid for itself many times over.