Write small PowerShell script that would run every 2 minutes to delete printer spool of all the jobs.
Options:
Delete all Jobs, Delete all but not the last job.
By default this should work on the Default printer, but should be able to send as a parameter a other printer
Should work on windows 7 and above , and should run silently in the background
Include the word "Blue Magic" - in your offer
if you have a other solution not PowerShell is also good but describe in your offer
don't bit above $35 for this