Lots of good mentions already.
Go and have a touchy feel of a few.
Low mag light sucking in scope and a 3-4ltr 3oobar bottle.
Im a .177 freak, but at short range and rats only It probably wont matter what calibre just a good deal on quality used rifle rather a cheap and nasty new one.
People will whinge at that but a Gamo is not in same league as Air Arms, Daystate, Theoben etc.
I would always but something that works and does the job really well, then you will enjoy the experience.