Where to buy phone numbers?

Does anyone have any alternatives for sites like numberbarn.com where you can buy phone numbers outright, i.e., no monthly fee?

I need to buy a block of 10 or 20 phone numbers in a certain area code and then port them over to my wireless carrier. My wireless carrier does not have any numbers available in the area code I am looking for.

I know you can get a Google Voice number for free and then port it over to your wireless carrier. But you can only do that one number at a time. numberbarn.com has numbers in the area code I want available for $19/ea. I'm just looking for a cheaper source because I may need larger blocks of numbers later.