Prepaids are actually pre-paid interest. If you negotiate in the purchase agreement that the seller is to pay for the buyer's prepaids, they then can get taken care of within escrow.
Also note, that because prepaids are just pre-paid interest, at the end of the year, you can claim that amount as interest that has been paid, but verify that with a competent CPA.
Prepaids also include HOA dues, depending on assessment dates. The prepaids are closing costs but in my state we have to put "closing costs to include prepaids" into the special provisions. I would think it may vary by state.