I've been busy researching on a good & economical USA East Coast Tour and I'm really lucky to find this website call GotoBus.
This is the link to the US East Coast Tours that I'm eyeing .......
It's also interesting to note that this website also sell bus ticket and cover tours in majour USA cities, like Florida Tours , Boston Bus & Tours and Los Angeles Bus & Tours and popular sight seeing spots; like Niagara Falls Tours , Grand Canyon Tours , Yellowstone Tours etc
If I've known about this website earlier, I'd signed up with them for a US West Coast Tours during my last trip to San Franc last year since they also cover Yosemite Tours !
Next trip to USA, I'll deinitely sign up the Las Vegas Bus & Tours !