Which DSLR flash should I choose?

Hi, I'm pretty new to DSLR photography. I have had my Nikon D5100 for a few months and I'm currently studying an online course… Haven't quite learned about flashes just yet, however I'm now being asked which one I might want for Christmas! Honestly, I have no idea. Wondering which flash would profit me most for portrait photography?

Unless you are dong to do a lot of event photography, the Nikon SB400 will do what you need for your class.

On camera flash is perhaps the WORST kind of lighting for shooting portraits. You need at least two light sources, a key and fill light and those are usually mounted 45 degrees from the cameras lens axis and sometimes above the photographers head.

So you can forget the flash for shooting portraits unless you plan on buying two.

For most profit a small studio like flash on a stand and some reflectors (bought or home made) would be the go,

or get a nikon sb whatever and a stand and wireless trigger set up

or just a sb something on the camera (icky - on camera flash is icky-ville)

or a generic flash than will go on a nikon, and better take it off camera with a wireless trigger set up