A Samantha shop is a computer generated shop from Marketforce, designed to look like a shop offer from a scheduler named Samantha. The bonus is generally more significant than the $3 offers. I think it is based on your past history of doing that particular shop. I don't think I have ever gotten an offer on a shop I hadn't done before. She is still around, I accepted 2 last week.
I have been lucky lately with MF. For the last two months, I have received a phone call from a very nice female scheduler (I can't remember her name) who asked me to do one of my favorite burger place for them. The locations were in different communities about 30 minutes from where I live. I was offered $30 for one and $40 for the other shop which I jumped at. I also get the emails offering a bonus for the same burger place for a stinking $3.00!!! Needless to say, I don't respond to the emails. I don't think the $3.00 would pay for the gas it would take to get to the locations.