Directron offers the Thermalright VGA Heatsink for ATI Radeon Graphics Cards
, model no. VRM-R3, for $16.99
plus around $8
for shipping. That's the lowest total in-stock price we could find by $7, outside the mention below. This heatsink features double 6mm heatpipes and is designed to passively cool ATI Radeon 5850 and 5870 video cards using the airflow from side panel case fans.
A close price: mwave has it for $24.99 with free shipping.