Body only is $519...
Nikon D5100 Digital SLR Body at Memory Express
Nikon D5100 Body - 33853
Body + kit lens....$639
Nikon D5100 Digital SLR Kit w/ 18-55 mm f3.5-5.6 G VR Lens at Memory Express
If you're getting it as a gift for your gf...I would prob just go for the $639 (and price match it?)
If not, I would just buy it separately...buy the body for $519 and you can find the 18-55mm lens in 10/10 mint condition on Craig for around $70-90.