Are there any merchants that offer split payments? One of my sites sells other members' products and a fee is due payable to my website. So, a product will sell for $35 and we take a $2 fee for every transaction. The total charge is $37, and we want $35 to go to the member's account and $2 to go to our account, in one transaction. Is there a merchant or script that offers this feature?
No. This would require you to have an aggregating merchant account which is prohibited by every processor that I know of. You cannot accept payment for another business though paypal or any other standard processor. There are providers that can support this, but it is very expensive (10%+ in fees) and usually requires large cash reserves. The best way to do this would be to have your sellers accept payment directly and then charge them per transaction, either through a pre-pay credit system or with a monthly/daily/weekly invoice.