you're getting ripped off if you're paying US7-9 for a copied LP, I wouldn't pay more than 6
Just like all the US tourists happy to buy cheap Tshirts in Vietnam for US$5 when you can easily get them for US$1.50 without much bargaining skills at all
Average price in Thailand is 2-400 baht, Cambodia is $3, and Vietnam is around 60,000-100,000. Of course you never pay the stated price, shoot for half and have fun with the bargaining. This is a heavily traveled part of the world so it is also very easy to trade at a hostel before leaving/first arriving at a country. Safe travels.
I lost my original guide book and bought one off some guy on the street of HCMC in Vietnam. The book was wrapped in plastic and when i unwrapped it the day after i found out there were about 100pages missing.