What store did you go to? I just got T2: Judgment Day for $9.99 on Blu-Ray at the Bitters store this week. It seems like most are 14.99, 17.99, or 19.99. You also have to shop regularly to check for deals. Any store can also check the inventory of all stores if there is something specific you are looking for. The also have a frequent buyer card. You fill 10 spots, you get a used item up to $9.99 for free. Two cards gets you a used item up to $19.99 for free. I'll bet I'm in the top ten card cashers in SA.
Non Disclaimer: I am not in any way affiliated with CD Exchange, other than as a very satisfied customer.