Amazon offers Prime members the NZXT G10 Aftermarket GPU Cooling Bracket for $19.99. Clip the on-page coupon to cut it to $14.99 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping adds $8.50.) That's the lowest total price we could find by $19. This cooling bracket is capable of 19 different liquid cooling solutions.

Update: Note that this item is temporarily out of stock, but can still be ordered at this price for delivery when available.