Hotels set their price, and generally they have to offer the same price through their chain’s website that they offer through online travel agency sites like Expedia or Hotels.com. Online travel agencies get a commission, but usually aren’t able to reduce the hotel’s price. If they did, you could claim the chain’s ‘best rate guarantee’.
But a membership website isn’t going to be subject to a best rate guarantee. A new one promises big savings, rebating their commissions, and is giving away free one year memberships — and a reader will get $500 to spend on a hotel there as well.