When you pay to rush build something the cost should gradually go down though. The first time you build something it's a prototype so it's more expensive but when you start mass producing it, it should get cheaper.
For example the very first Ford T may have taken weeks to build, but once the assembly line was built to mass-produce it, one could come off it every 5 minutes or so.
The same can be said for technologies like VCR's. At the very beginning in the early 1980's they cost close to 500$ to purchase. The last VCR I bought cost me 28 $.