Newegg has Ridata for $10, but shipping is $6
http://www.newegg.com/Product/Product.a ... 6817132051
Buy.com has a verbatim 4x 2 pack for $35 but is free shipping.
http://www.buy.com/prod/verbatim-blu-ra ... 69223.html
The verbatim seems more costly, but once you factor in the $6 shipping for the ridata at newegg it's only 1.50 more per disc. Plus I'd take verbatim over ridata personally... and it's 4x instead of the 2x ridata.
Staples has sony 2x media for $20. This is high, but it's nice to know you can find it locally if you had to...
Man this SO takes me back to 1996 trying to find cd-r media under 10 bucks a pop. And that was before anyone shopped on the internets... best buy and the officemax/depot's were the only game in town.