Also read man. Knowledge is power. How to Rock Climb by John Long covers the basics, Freedom of the Hills by the Mountaineers is a great reference, though it covers more than just rock climbing. Reading one of those before paying for a lesson may greatly increase your learning curve. There is a ton of info out there and some is outdated. Finding a mentor who has been climbing many years, or hiring a guide, can really help you weed out some of the junk, and help you learn concepts, rather than "rules". The gym employees who give "top rope classes" vary in certification, experience (both teaching and climbing), and style from teenage kids who learned yesterday to highly certified professionals. If the class is cheap, like 20 bones, you don't have much to loose. If you are dropping a bill or two look for AMGA (American Mountain Guide Association) guides or one of the few senior guides out there that didn't go the AMGA route. Next rock season the EMS Climbing School will be offering many outdoor group lessons in the MA. Oh, and never PAY a belayer... I can imagine someone just like you at that gym paying someone next to you to belay them while you pay someone else to belay you. Later down the road it is customary to "thank" a mentor who took you climbing with an apres beer or two... provided you are of age.
Welcome to your new addiction.