A Schrute Buck is an internal currency; a tool of motivation launched by Dwight Schrute. The value is worth 1/100th of a cent (or SB$10,000 to $1), about on par to the Indonesian Rupiah. Dwight makes 1,000 Schrute Bucks redeemable for an extra 5 minutes of lunch break.
There is no currency exchange rate between Stanley Nickels and Schrute Bucks, as Stanley said that it's the same as the "ratio of unicorns to leprechauns."
Later on, another office employee copies a multitude of Schrute Bucks and carts it into Schrute's office to exchange for $200. Schrute tells him that they're counterfeit. The worker retorts that "Yes, I'm here for the reward." When Schrute tells him that there is no reward, the employee threatens to "float the currency" and make it worthless.