A pistol scope has long eye relief ,which is about arms length.Simmons UTG,NcSTAR have good less expensive pistol scopes,all can be had for under $100......some older Tasco can be good.....I have pretty much went with Burris,though also Have Nikon and Leupold....all are above $200.
Got to say my Simmons and NcStar worked out well for me.I am looking at them now,the Simmons is a lot smaller ,but the NcSTAR is easier to see through.
If you decide to make your Prod into a carbine the Bugbuster works out Good.
It is about eye relief and how you are going to use your Pistol.....some people use Red Dots for shorter distance.
Another thing to remember= it is Hard to use a pistol scope "free hand" ,when doing it a lower magnification will suit you better.