I had problems with a molar that had received a root canal about 20 years ago. The dentist told me that it had to come out, but I had several options:

-Leave the hole, and the surrounding teeth would gradually fill in the space (I still have all my wisdom teeth, so that wouldn't be an issue)

-Have a partial plate inserted

-Have an implant inserted

The insert was quoted at about USD $5000. I found that I could have it done in Costa Rica, by US-trained dentists, for less than $1,000.

I seriously considered the Costa Rica route, but ended up just going with the gap.