Express Water via eBay offers the Express Water Reverse Osmosis 5-Stage Under-Sink Water Filter, model no. RO5DXC7, bundled with seven replacement filters, for $138.95 with free shipping. That's tied with our mention from a week ago, a savings of $220, and the lowest total price we've seen. It filters up to 50 gallons per day and features BPA-free parts, quick connect fittings, and a long-reach drinking faucet.