Spiffs is a slang word for dollars paid by manufacturers or distributors to retailers/retailers’ sales forces in order to motivate (incentivize) retailers/retailers’ sales forces to do something sales-promoting manufacturers or distributors seek to have done. That is, spiff is slang for push money. The preceding statement is: True, spiff is the actual word False, the actual word used to describe push money is spark. False, the actual word used to describe push money is spunk or spunky, as in "spunked them."
A spiff, or spiv is slang for an immediate bonus for a sale. Typically, spiffs are paid, either by a manufacturer or employer, directly to a salesperson for selling a specific product.