While I believe that PMC has discontinued this round, it is still available from a number of vendors, ranging in price from 54 cents to 74 cents per round. You can see the availability at this link:
PMC .44 Special Ammo as cheap as 54c per round
I doubt that an FFL dealer will pay anywhere near the prices listed above so you'll want to sell it yourself to maximize your return. You might try listing the ammo here on the Forum in the classifieds. Good luck with your sale.