Tamron lenses tend to be the same price everywhere and don't get taken by a bunch of extra junk you don't need in "packages". Looks the the price right now is $649. If you are near a camera store, get it there as it's easy to return if needed. Now, you might be able to save yourself about 20% buying used if you can find one in excellent condition. BTW, had mine for a while now and am very pleased with it.
I drove 90 miles to the closest camera store to check out the 18-400...got them to match on line prices with the Tap In Console...but was $50 higher due to taxes. The deal breaker for me was their return policy...10 days for in-store credit only. Went home and ordered it from Adorama. I'm in the process of doing the 'Tap In' focus adjustment...a real trick. Hoping to give it a good field test today.