Front just need something to pry\push the piston back...large flathead worked if I remember correctly. Unscrewing the brake fluid reservoir cap first makes things easier.
Backs need the caliper tool that twists and are much more a PITA.
I simply use a flat screw driver and press each cylinder back a little. If you do that, you'e got to do each one separately and just a little because as you move one back, the other (next to it) come out. Play just a little and you slip the new pads in pretty easily. As has been mentioned, the rear require the tool that turns them back - you can borrow from the auto parts store or buy for about $30.