It may not be worth it in the long run if it is for a few hours and you don't want to pay much in childcare cost.
We find our babysitters through our friends or our church's youth group. We tend to find a few from church that we like and rotate through them regularly. I also do a kid swap with friends so I can have a few hours each week to volunteer at the kids' school, go to dr. appts or just sit at home and do nothing but enjoy the silence.
I would ask around your SAHM friends and see if one of them was willing to do it for a minimum price. Sometimes Moms are willing if the kids get along...it is a playdate and they get paid..and it is at your house.
Good luck and best wishes!!