So, I tried to see if this had been asked before, but alas I couldn't find anything so i'll just ask. Being that there has been no american release of Battle Masters, and I've never owned a PSP so I thus know nothing about them, I need to know if I can buy an american psp and play battle masters or if I have to buy a japanese PSP.

PSPs are region free.
Only DLC is region coded to the game.
You can play JP DLC for a JP game on a US PSP, but you can't use US DLC on a JP game. Doesn't matter with Battle Masters as it's only been released in Japan.

Awesome! thank you! I'm looking to invest in a PSP as well as battle masters so I needed that info before I rushed out to buy one lol

You'll need a .jp PSN account as well as .jp PSN cards in order to get the DLC, keep in mind. I used these guys for my PSN cards:

http://www.japan-codes.com/psn/