If you're thinking about pcp, you are going to need compressed air. I would start looking as to where you can source this from. This is because an air tank is, by far, the easiest way to charge your rifle. The more you love to shoot your rifle, the more air it will need. So this leads to the question of what size ? A 7 or 12 litre bottle at 300bar is ideal. I've always thought that buying a brand new cylinder is like buying a brand new car. Peace of mind. Untouched by those who think and touched by those who know. When you have 5 years of use, the initial cost isn't that bad. After 5 years of use, retesting the bottle gives the feeling of a car passing its mot, and another 5 years of use.
Now you've got the means of propulsion for your pcp, then it's time to buy the rifle.