[crasher455]

I've seen used SpectraPhysics 820 and 825 co2 lasers for under $25,000. There in the 1.5Kw to 2.5 kw range.
I had an Amada lasmac 644, at my shop with and 820 laser and It cut 1/4" steel well.
If you fine tune your focal hight and gas presure you can cut 1/4" steel well at 1100 watts.
The main downfall to these lasers is there size. They have a footprint of about 6ft cubed + you need a large water chiller, and three gas bottles.