The site shows $80/month as the rate for King sheets, and I'd need 2 extra pillowcases as well.

My cleaners will change and wash sheets as part of their visit, which is less than $80/wk (yes, I'm comparing monthly and weekly pricing, I know).

$80/month is $20/week. In most areas you could find a service that would clean AND change the sheets for you for similar rates.

I can find decent quality king-sized sheets on Amazon for $20-$25 (and free shipping with Prime). It's essentially the same price to throw out my sheets every week and replace them with new ones (in reality, I'd wash them first of course, but washing sheets is not THAT much of a hassle)

IMO, the pricing for this would have to be much lower, like $10/month, to make it a cost effective service.