Yes - that cost on the rules pages refers to the server cost of the RMs needed. In most cases, with costs for prospecting, mining etc, RMs will cost twice that. Then there are construction costs on top of that. Then there is pure old greed and inflation that increase the price yet again. Generally, the producers have the lowest prices around - everyone else generally tries to get a profit above that again.
Actually, it does make sense. Material price for a product make up a maximum of 50% in real life. The producer then has to add production costs (machines, infrastructure, salaries), development costs etc. Add, that the rules page raw material price is only that (mining the materials is actually more expensive) and you should see that a 20x factor on the final sale price not that unrealistic.
If you think that's wrong, you can always create a shipproducing faction and sell your products at the (clearly stated) rules page raw material price.