Launch prices
The Nikon D5100 shipped in the US market from mid-April 2011, priced at around $800 body-only, or $900 in a bundle with the AF-S DX Zoom-NIKKOR 18-55mm f/3.5-5.6G ED VR lens.
Current prices
While the Nikon D5100 started at an MSRP of $900, the best price right now is $650.
