For the 2 photo shops, if the location does not have a convenience store (which actually happens here in NJ), I've gone as low as $9 plus reimbursement. I use enough fuel that I consider the reimbursement as income. I'll go as low as $12 plus reimbursement if they have a store.
With that said, I'm doing quite a few for $20 and up this week. There are a lot of these stations here, and a lot of shoppers to do them.
For the audits, $15 plus reimbursement is my absolute minimum, and that needs to pretty much be around the corner. I generally will only go $20 and up. I find the reporting to be a pain in the neck. I can get the on-site portion done in 15 minutes if I hustle.