First thing you need to realize is that some people online are not 100 truthful
No matter what price you can find they will claim they paid less, some of these people most likely don't even own a Tundra to begin with.
Want a good price? Then sell your trade yourself. Many of the great prices you are seeing are because people get a good price on the truck, then take it in the shorts with their trade, but they don't admit it.
Where I live Toyota is offering a $2,750 CM rebate and local dealer is adding another $1,585 off. He is the only game in town so I would guess in a larger city with a couple of dealers it should be reasonable to expect to get about $5,000 off the MSRP, maybe a tad more on a clean deal without a trade. Some of the dealers print their own "stickers", jacking up the prices, then people think they are getting a better deal.
A nicely loaded CM, 5.7, 4x4 loaded with SR5 , TRD, Entunes and a few other goodies is going to run 41-42K. With some luck you might get it for 35-36. Just remember, the more you see these trucks discounted the less they are going to hold their value if you plan to get rid of it in a year or two.
Walk into a dealer that is close to you and who has good customer service and make him a offer. Hand him a check for a deposit and tell him if he accepts it you will buy the truck today. All the BS about running back and forth is for the birds because the only thing you will end up with is maybe saving a couple of bucks and a lot of aggravation.