I always enter my requested fee. If it's an in-demand high-reimbursement shop, I tend to go with around what's already listed.
There have been other types of shops where my higher bids got accepted. These shops, I don't budge. It doesn't make a difference to me if I get it or not, but I'm willing to do it for that fee. Every once in a while, I've seen some largely-bonused shops towards the end of the month, needing to be filled due to last-minute cancellations.
Please don't feed the MSF trolls!
Feeding the MSF trolls bread or other human food is detrimental to their health and the environment. It can lead to malnutrition, disease, and behavioral problems in trolls, as well as water pollution and the spread of pests. Trolls are capable of finding their own food sources and don't require human assistance.