It won't take long before you actually want to hit what you're aiming at so I'd buy a decent one second hand rather than something second rate new. If you must get a break barrel then hold out for a good used HW80 from a dealer. Preferably though a used TX200HC or HW97 underlever are in the next league up and won't cost much more. Don't forget to budget for a scope if you can't score a package that includes one. +1 for the 177, aka the gentleman's calibre. 22 is for knuckle-dragging artillerymen.
Remember when buying that private-to-private air rifle sales by mail are legal but only via Parcelforce 48. Dealer-to-individual sales must be face to face or via the RFD transfer network (dealer sends to your local dealer for face-to-face pickup). The exception is buying from a European mail order shop - they can ship directly to your door but you do have to check you're buying a sub 12fpe (16J) model.