Replacing your brake pads might be an easy job, if resetting your brake pistons wouldn't be a tough work. Sure, there are tools available for 25$$$ and more. But why not just cutting two threads into your old braking pads?
1. Drill some holes.
2. Cut some threads into those holes.
3. Just use some screws to reset your brake pistons.
4. Be happy how cheap and easy replacing brake pads can be ;)