I say get a new one, but time it right when there are sales on MF or GC. If it's still too much, save up for it. It's worth it, IMO. That's what I did, AND caught my LMIII on sale. I paid $539, I think it was. I just saved gig money for it. Markbass is really good stuff.
Then again, you might do well with used stuff, too. I just like to buy new, myownself.