First time doing portrait photography?

I'm gonna start off with a little background information. I've been into photography for a few years now. I use a Nikon D40, with the 18-55mm lens and a 70-300mm lens. I'm mostly into landscapes/wildlife/nature photography, but I have done a few portraits of people/kids.

I've had several people ask about me doing some portraits ( some of children, another would be a couple's portrait) I am a photography major, so it would be some great experience for me(plus help kick off my career) and the extra money would be awesome. BUT I am completely new at this sort of photography so...

How should I charge per session? Since I'm a new photographer I don't want to put an outrageous price on sessions.

Also, should I charge per picture? And is it best if I print my own pictures, or have them printed at a store?

I don't have a lot of equipment, aside from the camera and lenses I have a remote, a polarized filter and two other filters.

I am on a tight budget, so going out and buying a studio and a bunch of extra equipment is totally out of the question as of right now.

Any tips and/or links to helpful advice will be greatly appreciated!!