If you're interested in modding, the cheapest and probably best way to go is with a Madcatz SE. They're super easy to mod, and relatively cheap in cost ($50ish). You can get cheaper ones, like Hori, Mayflash, and such, but they're a ***** to mod and they won't last very long if you don't.
If you're not going to mod, then that's a whole other story, and can get somewhat pricey. Art modding can also get kinda pricey with a higher grade stick as well, because you usually need to buy a plexi and stuff.
Long story short: go with a Madcatz SE, and you can always order better parts to mod it later, and it's really easy to mod. Art modding on the SE is pretty easy as well if you've got a local FedEx, Kinko's, whatev. :3c