I got mine at CompUSA with the Thermaltake GeForce 4 copper HSF (which I am not using, since the damn stocker is epoxied on) for about $12. Last I saw it, it was $16. They also carry either aluminum or chrome plated (not sure which) Themaltake ramsinks packaged seperately for about the same price.
Also, the 4-piece Thermaltake ramsinks in question line up perpendicularly to the ram chips on the card, but you can cut the sinks in half, yielding a top and a bottom for each chip, with a Dremel, enabling proper orientation.