So ASIC can be quiet cheap when you compare them per individual chip price, but it's a big start up cost for the designer. FPGA's are more expensive individually, but you can do more with them, and on a small scale the cost is easier to pass on without hurting their accounts.
Thanks. Yes, basically the more ASICs are produced, the lower the cost per chip becomes.
I'd estimate the Block Erupter chips (just the chip) will only be $5-15 a piece ...
In fact, the margin cost per chip is less than $0.8 a piece, that is hopefully $0.8 per GH/s. Of course, if we consider the cost of heat sinks, fans, PCBs, power supplies, and the disperse of the initial NRE cost into each GH/s, it will be significantly higher, but still within a single digit dollars per GH/s.
As it stands now, at the very least it looks like that will be roughly 10MHs:1$ ...
If only considering the whole production cost, it is easy to achieve more than 100MH/s : 1$. The actual market price is another story of course.