I just did the above image with a very simple setup using a single spotlight. (I used a procedural texture attached to the light intensity to give a bit of variation in the spotlight beam).

It's not a particularly good example, but it shows you don't need to buy lightsets at all. Everything you need is already there in Poser.

 

But to be honest, I first learnt these things using Saintfox's Fiat Lux lightset, which I can recommend. You get lots of nice light and atmosphere set ups to play with, and you can start with one of those, learn what the various settings do, and adjust to suit your subject.

 

Shall I describe the basic setup for an image like this, or are you happy to go play by yourself?  :O)

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)