I have used and am very satisfied with,
http://www.tonerrefillkits.com/
For the first refill you need the toner and the recharge kit. I have re-charged cartridges for this printer
http://www.tonerrefillkits.com/HP-Laserjet-1320-Toner-Cartridge-Refill-Kits.php
and and can not detect any differences in the OEM and refills for toner transfer. They also sell a ready refilled cartridge at about 1/2 the OEM price.