IMHO, $5000 is an absolute bare-bones minimum. You'll be spending that much alone buying stock. Are you going to be retro only, or are you going to include current systems also? If retro, I'd recommend $10-15K. If new, (and this is a ballpark figure) $25-30K for startup. Also, you'll need proof of insurance to whoever you'll be renting from, on top of payroll costs. Hope this helps.