You can always tell the people who have yet to experience a symptom of RSI.
"Splurging"? A one-time cost of maybe a thousand dollars? For an employee whose value is presumably somewhere north of $100 an hour?
If you can't raise the money for a decent desk by, say, the fourth month I think it's reasonable to question your company's future. Find cheaper office space, spend a couple of days consulting, pick stuff out of the dumpsters in back of a larger company, whatever, but get yourselves some decent tools.