There are a fair few options dependant on volume . All is possible and some mould tooling can be done very cheaply ,but you're still talking a fair few hundreds ................+ the moulding and moulding setup charges .
Rapid proto SLS .....A laser solidifies the shape in a tank of plastic resin .This has come on leaps and bounds in the last few years .I can model up a unit in 3D given a sample and then the worlds your lobster ,the more the cheaper .
I model up a lot of O gauge trains for a local outfit and they also do their own resin stuff for lower quantities ..
Send me an original and I'll check it out