Pellets
It matters if you want to do well, the difference in price to a 500 tin of RWS R10 (£8 ish), and a cheapo is the cost of a coffee, nothing.
That's the bonus of shooting air, the top ammo is cheap. If you want to know the bad shot was you, buy the best, if you don't care buy cheapo's and you'll never know!
Have Fun
Robin
Walther KK500 Alutec expert special - Barnard .223 "wilde" in a Walther KK500 Alutec stock, mmm...tasty!! - Keppeler 6 mmBR with Walther grip and wood! I may be a Walther-phile?