Cheapest place I think is newegg.ca they are $100 - $10 coupon NEWCUSTOMERCA and free shipping
Newegg.ca - SAMSUNG 840 Series MZ-7TD120BW 2.5" 120GB SATA III Internal Solid State Drive (SSD)
You may have to make a new account (or 2).
That drive uses TLC nand I believe, TLC has the lowest endurance of the 3 types of NAND.