I've never heard of a carburetor going out, or going bad. Typically they just need to be rebuilt from time to time. That's not a big deal. Your average mechanic can remove, break it down and rebuild them in less than an hour. I had the one on my boat rebuilt and they were able to remove, rebuild, and re-installed in less than 30 minutes ... but that was on a boat and it was extremely simple and accessible.
If you have it rebuilt, I would look at spending $60 - $80 for a rebuild kit, and at least one to two hours for shop labor. The average going rate seems to $60 - $90 dollars per hour.
For $800 you can buy one of Holley biggest and baddest carb's and have it installed, let alone perform a rebuild on yours.