Dude, using a sawzall will tear up blades, take you a while and will do nothing but frustrate you.
If you bring them to a shop, they may want like ten bucks to dismount 3 tires. I don't know about you, but my time is money. I tired the sawzall trick years ago and it sucks...

I was tired of paying tire shops to do mounting, dismounting, etc. I found a like new, Coats 40-40 for $125 and bought it and its a great machine to have! Now I do all my own tire work. Soon after I bought the tire machine, I found an older Snap On Wheel balancer for $250. Now I am totally self sufficient!