Hmm, nice to see some helpful advice in here, I don't have much unique to say so I'll just end up echo-ing others...
As far as NEO•GEO goes, in my opinion, the absolute cheapest method is to go MVS+AES. Get yourself a hardware set up that can play both and just buy whichever game is cheaper on either format. I say this because earlier titles like NAM, Magician Lord, Blue's Journey and Thrash Rally are actually harder to find and more expensive on MVS than AES. In fact, you can still find New Old Stock copies of early AES titles for good prices. Not to mention, most people switching 100% over to MVS drive more demand for such games. You can find AES versions for cheaper. Otherwise, the MVS version is either at the same value is much, much cheaper.
Oh and on the subject of MVS at home, nothing is more inexpensive than just making your own Supergun (or if you prefer, making your own CMVS). The parts are easily available, plastic cases aren't hard to obtain and the making of a Supergun or CMVS is essentially just passive wiring, excluding the video encoder (you can save even more money and make that too if you want).
@Thunderblaze16: Don't forget about DavidG's Daedalus Converter, $400 and you have a 100% perfect MVS converter. OR, you can use one of his guides and PCBs to fix a pre-existing converter, like the Phantom-1, Pranslation and Super MVS Converter 2.
http://www.neo-geo.com/forums/showth...oGeo-Converter
NEO•GEO is definitely a great piece of arcade hardware, but yeah it's not for everyone. Before you drop serious cash on the system, make sure you're actually interested in it's brand of games, both it's staples and array of strangeness.