Need some feedback before I spend!!

Hey everyone!! So I've been on a hunt for local contests in Toronto. Been asking around SmartCanucks, friends, etc... Honestly - looking real hard. I'm sick of big contests by big companies. I was looking for contests at small local businesses where I can win prizes - I'm kind if hippy that way .... I don't like shopping at Walmart or big chains.
Anyways I had a friend that knows a friend who heard of this new company in Toronto that has contests at local business. The company is called Addibuy. I checked them out online and I'm not 100% I understand but it seems like u can win prizes by bidding during the contest (the goal is to be the last bidder). Each bid is always a $1 and that everything u spend during the contest u get back as a credit to the store holding the contest. Seems kinda cool. Again not a 100% if its legit. They have some pretty good businesses like Boston Pizza, Menchies, Marble Slab. Lots of prizes. They have a Moksha Yoga contest that I think I'll try - but I wanted to get some feedback from people (if u ever tried it, what u think) before I put my credit card and spend with these people. Let me know what u think!