I use a Hawke Varmint 2 3x10x44 on my rimfire (£120), a Hawke Reflex 6x40 on my air rifle (£55) both are excellent value scopes with mill dot reticule. There are better and more expensive scope available but I have had a lot of success with these models. Remember you will need a set of good mounts otherwise you will not get value from your scope.