I have to say you can’t beat Alienbees. I have two of the B800’s I use for portrait and copy work. They’re about $300 each all told. The B400’s are just as good, and if all you’re doing is portrait, I doubt you’ll need more.

When You use Bowens for the firs time,You’ll never stop.

If in the US Alienbees are a very good option. In the UK have a look at Lencarta or if you can afford it Bowens.

You probably want to get a kit that includes a couple of light stands and flash heads but the types of light modifiers get in a kit tend to be umbrellas which are not the best. I would recommend getting softboxes and a beauty dish with grid.