Yelp is the devil, but many food people worship that devil. lol
We have a brick and mortar location and I tried advertising with Yelp a few years back.
At that time They limited their clicks to a max cost of 300 per month, but you had to pay for the full year. So we gave it a go. Yelp, they have all these reports that tell you how many clicks ect, but I never saw an uptick in business. I still have access to that info and I get the same results now from the free yelp, so I think it was a complete waste of money.