It's a good price no doubt, but based on wattage, not a great price. For instance, the turbo-twist 18w is listed as good for up to 250gal. Yours is listing half the wattage & 4 times the capacity. So, I'd say they're a little ambitious with those figures.
I've seen the turbo-twist 36w listed on ebay for $100, & the 18w listed for $75 just to let you know where you stand.