For $50 a week you could be taking 100 visitors away from your competitors site and driving them to yours Track each penny spent, each click paid for and each success event (how many people you paid to come to your site filled in the form to get more info, or click the phone number?)
Only advertise where your customer base is and at times when they shop (don’t advertise to someone in Winter Park, Colorado)
Use negative Keywords to remove any chance you will advertise to someone looking for “Bicycle Rentals” when you only sell bicycles.