I bought three keys from one of those fly-by-night sellers on Ebay for a little more than $12. Only one of these keys worked. I bought a single key from CJS-cdkeys for $12, and they had to replace it twice before the key worked. So the cost was the same either way, but if the third one had not worked, I could still request a forth one. I bought from a seller (cjs keys) willing to create a website and return process for service and to eliminate uncertainty. The strategy was successful. Better to know I could eventually get a good key eventually than to get three keys that might not work. Very important advice to new purchasers: have your screen shot program ready, and when you enter the key (use cut and paste and put the key through a text-only editor on the way) take a screen shot and save it. Then, if the key works, you're done. If it doesn't work, take a screen shot of the rejection screen, and save it too. You will need these screen shots when you request your replacement key or refund. I gave four stars and not five because they put me through two faulty keys before I got a good one.