I've used Monkey Grip, too, and they work fine--but carrying that big can of cement is a pain, and I haven't found a way to keep smaller amounts from hardening. A couple of bike shops here will sell patches in bulk, 25 or 50 (I forget; haven't bought them in awhile) to a package, and large-ish (2-ounce?) tubes of cement separately. I have 25 or 30 flats a year, and it saves money and shopping trips.