yes, you can do it yourself....but I wouldn't suggest it without the use of an impact gun, and some basic experience working on your car in general though...it will probably take you most of a day also if you've never done it before...I think it's 2 hours shop time if you get it done
you should be able to buy an aftermarket inner tie-rod for about half the price of the oem one, but I can't help you on where from tho, I'm in canada
from the sounds of it though, I think you should let somebody else do it.
But not THAT guy tho. it shouldn't cost 300USD to get it done.....you should be able to get it done for about 200USD parts included at an independent dealer...
for 300, you should be able to get it done at a dealership
and that's some low miles for an 87