I did quite a few gas station shops in 2009 and 2010. Most of the time I saw them posted for $10-$12 + $1-2 reimbursement (small item inside, receipt required). I never accepted those dollar amounts, but that's what they would post at in my area. I worked out routes and bonuses with the MSC to get them done (normally $20-$25 each depending on how far a station was).
For kicks I decided to look today (with no intention of getting any) and I'm seeing them posted for $7-$10 lol!