Gas tank leak

[bops]

I am a new 91 318i owner just purchased. It has a gas tank leak. I am having trouble locating a replacement tank online. Am apprehensive to order in fear of it not fitting into the space and then being stuck with an un-returnable tank. Any suggestions would be very much appreciated.
Will a replacement tank from auto zone for 200$ be satisfactory? Any other suggestion would be very helpful. Thank-you!

[bops]

Yo could really use some help on this leaking gas tank. Am not sure if need to replace tank or if the leak can be repaired? Not even sure where leak is originating from? Ant kind assistance would be greatly appreciated.