The reimbursement is just over $17; the initial fee is $9 for regular shops (online and dine in) and $5 for delivery shops. Depending on where you live, that might not be enough, since prices for the required items can range between $17 and almost $23 with taxes. With a milkshake tacked on, the reimbursement goes up by $5, but the prices of milkshakes is $7 or more in some areas.
There are other things to consider, including transit fares, wear and tear on one's car, etc.
Depending on where you live, bonuses might be added, but nothing like say a year or two ago. Back then I could get an extra $10 to $25 on top of the regular fee, but those days seem to be gone for now. Now, it's another $3 to $10, and bonuses don't start until at least a week after the shop would have been normally due.
The reality for me is that I cannot afford to do these shops unless I'm already in the same mall or store next door, and I want to have lunch.
A good thing about them is there are no long narratives, and after gaining experience, I can enter accurate shop data online in 15 minutes. I don't do shops that include shakes, since I can't consume such a large quantity of sweets at one time, and the reimbursement rate is even worse than that for the meal.