They
can be cheaper to operate, but up front costs for buying one, HPS is definitely cheaper.
My 240 watt LED (actually operates at 133 watts) cost me $270, for that I could have gotten two 400 watt HPS setups, or one 1000 watt HPS setup. But I prefer LED, I've tried HPS, and I got tired of dealing with the heat issues.
CFLs are decent too, and are super cheap compared to any lighting.
So HPS is cheaper? i thought LED would of been way cheaper? :O