I would always say a nice 2 light kit is a good starting point and there's really only two respectable options here.
1. flashguns
2. studio lights
both really work out coming to the same cost, though many would say flashguns are cheaper if you go non-branded. In my limited experience nothing beats studio lighting, very dependable and easy to set up.
I hate to namedrop but Lencarta do good quality lights at a great price point so I would look there first.
Then obviously you need triggers (can be had on ebay for good price),umbrellas, softboxes, backgrounds etc all really to be brought depending on the look of the images you want at the end of it.