A-frames are a sturdy sign concept for many shop owners. These signs get their name as they literally represent an A when standing up. These are the signs you are used to seeing outside shops in downtown. Aframes are placed on the sidewalk each day for passerby's to see. You can change the message each day if you are running a restaurant for instance - for the special of the day.
A frames are a good choice because they are portable - can easily be folded up and taken with - and also, affordable. If you have multiple properties, a-frames become very easy to pickup, store in the car, move to the next location and setup time and time again.