Just an FYI for you - you should expect to spend more for a pistol scope
I use Nikon scopes and usually spend $200 or more...although you can find used Weavers at reasonable prices and I have always liked them and had good luck with them...but even used they are closer to the $100-$150 range.
as far as a red dot you may find a used one but make sure it is a name brand that can handle the higher recoil abuse of a handgun, especially if you are using it on a 44 mag or one of the specialty pistols in rifle calibers (.308/.243/30-06/30-30) like I shoot