Walmart offers the Intex Saltwater Pool Generator System, model no. 54601EG, for $129 with free shipping. (Amazon charges the same.) That's tied with last week's mention and the lowest total price we could find by $71, although we saw it for $10 less in October. This system has a flow of 700 gallons of water per hour and features a 24-hour timer.

Of note, this item requires a pump (not included).