I recently purchased a unit, the Kent Maxxima RO
24 gallons per day at Direct Aquatics. Their price was about $50 less than other sites but their shipping rate is pretty high. With shipping, the cost of the unit was about the same as the other sites that included shipping in the cost. THe only problem is timing. It takes forever as this particular company takes 2 - 3, (or 4 or 5) business days before they actually ship, then, their standard shipping rate is 3 days via UPS. In other words, it took a full 10 days from date of the actual order to get the unit and I live less than 100 miles away from the place.
There are all kinds of RO
units out there at a cost between about $150 up to $300 plus for the larger capacity. Since I only have about 50 gallons worth of saltwater tanks, I don't have a huge capacity unit.