Like a lot of mystery shops, depends on your situation. I do frequent restaurant shops for no fee. These are places I love to eat at but dont love the price. When the price for an $85 meal is $0 plus a report for someplace I like, I'm game. When the cost for a nice blouse is $0 plus a report, I'm game. When the cost for a $40 candle on sale for $25 that I want either for me or as a gift for mom, drops to $10 plus a report (that I've done before), I'm game. There are other things to buy vs the candle, votives, car fresheners - which I really love. My point is that I like these shops as long as they are reasonably close. I also like KathyG's idea about donating. Plus they make good basket items when I personally make a gift basket, new baby, wedding, holiday, get well, etc. The ideas are boundless as how to NOT spend MY MONEY
When you learn, teach, when you get, give. Maya Angelou