How much will it cost for a camera repair?

Does it cost a certain amount depending on the camera or the damage?
I have a Nikon D3100 SLR camera. I stupidly left it unattended on the dining room table and my little cousin grabbed the strap so she could pull it off the table, hitting the side of the lens as a result. Now it won't take pictures as fast as it's suppose to. When I take a picture of something it stops mid-shutter, then continues, and when I look at the pictures they're blurry or mirrored. Sometimes it won't take pictures at all. Is it just the lens or is it the camera, or both?
I know that's a lot of questions, I'm just really worried:/

Repairs will vary depending on camera & damage. Your average point & shoot is a throw away camera when it comes to repairs Damage can be both to camera & lens. You'll have to pay someone to look at it. Maybe $100.

$100 plus

WOW… That is a hard lesson to learn! If my camera is not around my neck, it is in its padded case.

It sounds like it is probably a shutter issue. The best thing to do is contact Nikon at 1-800-NIKON-UX (1-800-645-6689) and make arrangements to send both the camera AND the lens to them for a repair estimate. Be prepared for a $200-$500+ estimate.

I can't answer price wise for Nikon repair since I shoot Canon DSLRs, but a basic camera CLA (cleaning, lubrication, and timing adjustment) for my camera is $180 (plus shipping and insurance to them) and ~$350 for a shutter replacement.