In my area, the places that provide paintball tank fills won't touch any tanks as large as the 30/45/60 minute SCBAs we use. They only deal with 45-108 cu. in. tanks unfortunately.
At this point, I'm fully committed to filling my own tanks mainly because of how much money I have sunk into my Yong Heng compressor. Your right, and while the compressor is about $250ish, you'll probably end up spending at least $125-150 on a moisture filter, compressor oil and just misc stuff. IMO, some kind of moisture filtration beyond what the compressor ships with is a must, or you're going to have lots of moisture in your tanks. That's one of the benefits of using a shop for fills, their compressed air goes through a dryer. It's disgusting to think about it, but I'm probably close to $800 spent on my Yong Heng compressor setup. It's definitely not typical for YH owners to spend that much on their setup, but I've added/modified/replaced a lot of stuff on my compressor. I have 2 stages of moisture filtration, upgraded hoses/fittings/pressure gauge, and I keep a bunch of spare parts around for most any type of failure a Yong Heng compressor might have. I hate waiting 30 days for parts to arrive from China, especially if it means I can't run the compressor until a part arrives.