I've just spent the last hour reviewing the watersoftener business. It's huge. Affiliate programs @20% with sales ranging from 1000 - 3000 for residential systems and a lot more for commercial such as hospitals, restaurants etc. Some offer payment for life of customer on supplies and accessories. It also gets them into water filters etc etc etc.
I would expect all offers to reflect that I have not yet determined a price for the domain I usually let the offers guide me.
PS this is on other forums too and subject to "previous sale"