New connection possibly just have to out bid?

Local comp shop i stopped in to today sells to a guy for 15$ per load. Load averages 6 towers all the way up to 15 (hard drives taken out) depending on bizness for the period. He also throws in a tote full of power supplies and batteries and random types of boards.
Digging through the forum i find there worth 10-15$ a piece for a desktop(remember the H-drives on mine are gone) . If selling to a scrap yard and not a special guy what would a comfortable over bid be on my competition? Anyone in MN buying this stuff at a higher price? To my research the lot he gives each pick up is worth $100 am i correct on this?

Any help is awesome I know these questions are repetitive but this has serious potential so i thought i would verify.

You cannot go with the $15. profit for them cause of no HD's available.

my limit is $4 per scrap tower missing only the hard drive when I am picking up...remember how valuable an at their door service actually is...

When it comes to desktops, pay by the #. It's fair to both parties. It's best to have two rates, one for a complete PC and another for an incomplete PC. Complete must have RAM, HDD, and MB.