For some insight on how I do payment, I take living expenses, expected resource expenditure, necessary profit, and then throw on difficulty modifiers.  Since you are prime runners I included a couple months of high lifestyle.  A successful job needs to cover the time spent doing the job and the time between jobs.  If you guys go out and take care of him tomorrow then it is basically a bonus for a quick and concise job.  There are also a couple percentage points tacked on there for being paid in currency other than nuyen.