New key and remote for 2000 Ford Focus

No more than $20 for the fob and $15 for the key, if you buy on ebay. They are plenty of them on sale there, brand new, not used.

Dealer prices will probably be higher, of course.

If you have two working keys you can program a new key yourself, the procedure is in the owner's manual. If you only have one working key I you will have to pay someone to program in the new key. I have done a couple of keys myself this way, paying a local locksmith to cut blanks I bought on ebay.

I don't know about programming the fob but you can probably do that yourself also, again assuming you already have a working fob, but someone who knows for sure should be along soon to confirm.