They are different products. Ready Traps are bags that can be filled with the standard acoustic foam. Real Traps are a line of products, non of which are simply foam - though I never did see a cross-section of any so I may be wrong. I think they are tuned slightly, as opposed to completely broad-band. Personally I think the best bang-for the buck are "StudioTips Super Chunks" which are simple to construct and do a good deal of treatment...
http://forum.studiotips.com/viewtopic.php?t=536;