Search in your area for a local fire services/sales place, the kind that sells to fire departments. All but the really big guys do all testing on site, some of the big multi store/multi state places send stuff off and are more expensive, some on site. They "always" beat scuba places prices by a ton. Always is in quotes, someone will find the exception that I'm sure exists somewhere, I've never heard of one. In my area, the two I had done were less than a quarter the cost of any scuba place around here. The tech actually tested 3 tanks, but one could not be certified because it's manufacture date was too old. I never asked about that one, I knew, but the tech knew what I was going to use them from our talking about hunting and reloading, he told me to leave it there anyway. It did not get a sticker, he just told me it tested and inspected in spec but was too old to certify and no charge for running the test and the inspection on it.