Well if you didn't know, you can't just buy a PCP air gun and shoot it.
At minimum, you need a hand pump. They can work ok for low powered, small caliber air guns, but anyone here will tell you that they are not fun when if comes to high powered, large calibers especially semi autos. You will be spending orders of magnitude more time pumping up the gun than actually shooting it.
If you get a scba carbon fiber tank, that works, but you need a way to fill it which will either necessitate buying a compressor which is capable of filling a tank ( some are designed only to fill guns not tanks. Sometimes you can fill a tank with these with many cool down cycles during, but it is ill advised) or you will have to take it to a scuba shop and pay a fee each time you want it filled, unless you're friends with a fire station who will fill it, good luck with that though.
They have compressors that can fill a gun and work off of a car battery that could be taken to the range, but they can still take 5 min or so to fill the gun. So in the case of the terminator, you fire it 20 or so times which can happen in under a minute, then wait 5 min to fill it with a compressor. The most convenient arrangement in my opinion is a compressor at home to fill tanks and the largest tank you can get, but that's also the most expensive option, more than the cost of a terminator. The good news is if you have all that stuff, you can get more pcp guns in the future