Just think of it this way, there are many problems users will face and many of these can easily be solved by other users who are willing to do it for a small fee.
Take for example, John wants to convert a word doc to PDF format and he didn't know to do this. Hiring someone to do it will simple cost you nothink charging $1 (your revenue) for each job sold on the site, paid by the seller. Therefore the buyer pays $5 and the seller earn $4 and receives the funds via Paypal. With widewebpro script, the site owner can determine how much each job can cost, it can be even $10 or you can even set is as user defined cost per job.