First off Resin is expensive and the price has gone up with the hike in oil prices.
Second Silicon is expensive.
This stuff is hand made not just cranked out by a machine so paying someone to do it adds in.
Also for clean molds and copies they need to be preasure cast and the tanks are very expensive.
Also depending on the detail and the silicon used you won't get that many good copies before you have to replace the molds, ball park figure 20 to 30.
I have been buying garage kit's that range from $30 to over $200 and have seen rare or large ones going for well over $1000.
I have in the past also done some casting in a friends garage so I have some limited experience of what goes into it.
I've also visited a shop in LA that produces studio props (TV & Movie) and replica studio scale models.
Eric...