It’s going to be tough to find without being able to speak Chinese. Here’s a list of different places with prices and ratings: http://www.dianping.com/search/keyword/8/0_%E6%8C%89%E6%91%A9
The absolute cheapest ones that you can go to are usually the blind massage places (盲人按摩）. I’ve never actually been massaged by a blind person there though. You can expect to pay less than 50 for a full body massage there.