Two other options-
Leave the new tank in quality primer without going to the expense of final paint. That allows a buyer to save a buck and choose their final color, even if it is the primer that’s the recent cool fad.
If not, go black or red and consider adding some tape pinstripes for bling. Again, it’s less expensive and more flexible than real pin striping. Then the buyer can either later afford good $$ pinstriping or just pull the tape to have a solid color tank.