Personally, I use this for $20.

Smart Spair 15 Minute Emergency Tire Repair (#SS-PDQ/06) - NEW Slime Quick Spair & Slime Shield

It's not quite as convenient, as it is a two step process. First you squeeze the Slime into the tire from the slime bottle using a tube, than you inflate it with the pump.

But you can buy it for $20 at Sears and most auto stores.