Actually, be careful. On my 2000 Ford doesn't use the "PATS" system anymore. It's now the "Secure Lock II" or something like that. I think the term in is your owners manual. It's a slightly different technology, so you need to make sure you get the correct type of key. The keys for the Gen 3's are slightly different.
IIRC a new key bought and cut from the parts department is only about 25 bucks. You still program it yourself... more expensive to have them do it if you only have one working key, but if you have two keys, you can program it yourself and you just have the cost of the key.
Also FYI, I tried to buy mine online and I had it cut at Home Depot (in fact, someone in that section just did it for me for free) but as it turned out, the key was cut too far up the shaft and wouldn't turn in the lock normally. It ended up that you could pull the key slightly out away from the lock and it would turn, but it took me a little while to figure that out.. found out after I bought another key from the dealer. The dealer key worked perfect the first time though.
-Dan