Fuel tank question

[barmanvarn]

Note: I've yet to pull the old tank out of the truck and look inside, so there are some unknowns right now. But figured I'd start exploring my options......

At some point (way down the road) in the resto, I want to move to a tank between the frame rails, but for now I have to work with what I have.

A new stock tank looks to be around $150. I called a local radiator shop and their estimate to clean the tank was $250. WTF?

So my questions are:
Is that quote way too high?
If the tank isn't too bad, do I have an option of cleaning it myself?
If it is bad, and the quote is accurate, I guess I should just by a new in-cab tank for now?

thanks