Whats a NPV analysis?
NPV (aka net present value) is the sum of all cash flows (both cash-out and cash-in) discounted to its present value (what it's worth today).

Finally something relevant to my profession...enough with you programmers and engineers.
Edit: Of course every keyboard purchase has a negative NPV. The only items we buy/trade that don't are clacks and SSKs (with current market prices). Just look at the Korean keyboards...5 months ago they were routinely selling for $500. Now, you can get them in the classifieds, fully built, for $360. Besides, by its definition, anyone who has a positive NPV will be making money off the community.