A lot of wedding supply places don’t fill they only exchange which isn’t feasible if you have a power tank but I have had good luck with fire control companies (places that do fire extinguishers or fire systems in buildings) they charge like 15-20$ for a fill on my 20lb tank I use for filling tires.
Agreed, welding supply shop. Also, they can re certify your tank to ensure it is safe, then re-stamp it to prove it is legit. Cost a little more $, but it’s worth when you have compressed CO2 in a tank. At least that’s what they do here in NC, state regulations. It cost about $23 dollars.
I've been going to the local paint-ball place, but of the three near my house, only 1 will fill a tank as large as mine (15lb).. They charge $25 ..
I just found a fire equipment supply house not from from me that will fill it for $15, and a friend has been going to a welding supply place that also only charges $15 ..
Here in Utah I tried a paintball supply store and had horrendous results. They filled the tank but did not pressurize it so I only got about 6 tires out of it.
Next I tried a local welding supply store. They did a great job, but they take a long time. I always have to drop it off and then pick it up later that week or the next. It’s only 20 bucks to fill, but I wish I could find a place that does it while I wait.