Im sure you can cut that cost down by a ton if you did some of the work yourself.
If you are daily driving this car then it may be difficult, if its a project of yours then you can take the body off the frame (pan), not as difficult as it sounds, and deliver the pan itself to the shop, that would make it pretty simple, cut and weld.
that way you should be able to do it for about $500ish- $1000 maximum id say, take it home, spray the pan yourself with some por15, mate the body and your good to go.