I have one of the ultra-cheap .177 Chinese spring air rifles you see at gun shows and flea markets. I paid $30 for mine. It's lever cocking, not a break barrel, with the lever under the barrel. The thing is poorly made, the stock looks like it was made from a packing crate, the wood screws keep pulling out of the trigger guard, the plastic hand grip on the cocking lever disintegrated, but man is that thing accurate.
Although I can shoot rimfire .22 at my place, I more often take out the air rifle. Cheaper to shoot, very quiet, no mess of spent brass.
(BTW, I shoot Colibri ammo occasionally, but I find that its pure primer load is very dirty. My son's bolt action gets so fouled that the bolt is almost impossible to turn.)
I also have an inexpensive Crossman .177 CO2 pistol. It's not terribly accurate, but it works well for cheap practice and is great for teaching my wife to shoot (no recoil, quiet, etc.) My wife gets very nervous at the range, and doesn't like being the only woman on the line. Backyard practice with the Crossman is easier for her, not to mention convenient.
Air rifles and pistols, even the dirt cheap ones, are marvelous practice tools, and loads of fun for plinking. Get whatever you can afford, along with a bucket of ammo, and start popping away.