Try a Webley Tempest. Used ones are around $100 now; Beeman's is no bargain basement, but often has these available. New ones are maybe $140-$160. Cabela's has them at the low end.
They are good practivce arms though they do not duplicate the recoil of firearms. However, they force the same level of concentration in holding well and achieving good shot placement. Plus, they have really stiff but manageable triggers.
I thought such training was a bunch of hooey until I started practicing with my W-T over my Crosman CO2 pistol. It really does require more control on your part to shoot the former accurately. BTW, good MV, around 400 fps perhaps. My shooting improved quickly.
The firearms replicas may give you more familiarity for the feel of your gun, but if they're CO2 they won't provide the same discipline you need in a firearm. Of course, one of each kind would be very nice.
Some say the Beeman P1 is worth a look (used) but that may depend on the type of surrogate you require. Good luck.