Some of the co2 type guns can be a little noisy
A Webley Alecto is reasonable second hand. Depending on your neighbours worries about noise, as it makes a good crack on 3 pumps. I went for one to avoid c02 costs, and I can hit spent shotgun shells from across the garden on a good day. You can always get a later one with a threaded barrel for a silencer if noise is an issue.
***Proud Member of Castleton Air Rifle Club***
Thanks guys, appreciate the info.