[H]ot $399 for Denon X2100W AVR (orig $699)

This is regularly priced $699. I bought it 60 days ago for $549, which at the time was the lowest price it had ever been. So I am fairly said about this for me....

Crutchfield and Amazon tend to match each others prices (when one decreases so does the other).

So you can buy it at
Amazon for your Prime shipping,

But if you are concerned about Tax you can buy it at Crutchfield.

Crutchfield also provides 60 day returns while you can only expect 30 from Amazon.

Features and Specs
General
Number Of Channels 7
Stereo RMS Power (watts) 95
THD in Stereo 0.08 %
Frequency Bandwidth (stereo) 20-20,000 Hz
FM Sensitivity 12.8 dBf
HD Radio Tuner No
On-Screen Display Thru HDMI
Auto Speaker Calibration Audyssey MultEQ XT
HDMI Standby Pass-through Yes
Composite Video Conversion From Composite to HDMI
Component Video Conversion From Component Video to HDMI
HDMI to HDMI Upconversion Yes
Internet-ready Yes
Apple AirPlay Built in
App Remote Control Yes
Bluetooth-compatible Built-in
USB port for iPod/iPhone Yes
DLNA Certified Audio
Photo
MHL-compatible No
Multibrand Remote Control No
Learning Remote No
LCD Remote No
Width (inches) 17-1/8
Height (inches) 6-9/16
Depth (inches) 14-1/16
Weight (pounds) 21.6
Parts Warranty 3 Years
Labor Warranty 3 Years
Multi-room Audio--Video
Powered Multi-room Audio Output Yes
Preamp Multi-room Audio Output Yes
Multi-room Video No
Multi-room HDMI Output No
Surround Processing
Dolby Digital DD, DD+, EX, TrueHD
Dolby Atmos No
DTS DTS, ES, HD, HDMA, Neo6, 96/24
Inputs & Outputs
Phono Input No
Audio-Video Inputs 8
Audio-only Inputs 1
Component Video Inputs None
Component Video Monitor Outputs 1
Optical Digital Inputs 2
Coaxial Digital Inputs 1
Optical Digital Outputs None
Coaxial Digital Outputs None
HDMI Inputs 8
HDMI Monitor Outputs 2
Subwoofer Outputs 2
Multi-Channel Analog Input No
Multi-channel Preamp Output No
Main Speaker Output Pairs 1
Main Speaker Terminals Posts
Ethernet Port 1
USB Connections 1
Removable Power Cord IEC 3-prong