how much will it cost to fix my gas leak?

It depends on where it leaks from and what year is your truck. If it's the tank you may either try a gas leak sealer (basically a hardening puddy) or purchase the whole tank for a descent price. If it's the filler neck you may be able to get away with using a large diameter fuel hose. Replacement fuel lines are usually not too expensive and is best if your old lines are rusty. If it's up in the engine, you may only need to change some o rings or gaskets. Hope this helps.

If it is leaking from the tank, they also sell a tube that fixes gas leaks, its like gum and can stick on a leaking tank even while the gas is coming out for about 3-4 bucks.

If it's a small leak ,then run to the part store ,and buy the Sealer for Gas Tanks ,It will take you about 15min. And about $8

Good Luck

It can cost up to $700 if it is really bad