Take a look at this one ... use the drop menu on the watt section and you'll see that the 400 watter is just $5 more than the 250 watter!

http://www.mdhydro.com/ht-high-pressure-sodium.html

The most economical I have ever found is this "Econo Version" from Inside Sun for $75. (scroll down a little)

http://www.insidesun.com/

hope this helps,
Max Blast
Max Blast Reviewed by Max Blast on . HPS lighting How well would a 50W HPS light work for a very small set up? Say 5 plants tops. I am thinking about getting one, and supplimenting it with flouros as well. I am just now working up some box designs. Rating: 5