Looking at all of the mounts available for the GoPro HD, I had a bit of a problem with some of the prices for 'em. In particular, the suction cup mount from GoPro. It's priced at $30.
If I didn't know better, I'd say that seems a fair price for a versatile device. However, I've seen this type of mount on eBay for a lot less!
There are many for under $6 with free shipping! Just search for "car suction cup camera mount" on eBay and you'll find lots of these mounts:
To me, they are identical looking to the GoPro model. Functionally, the only difference between them being the tripod mount instead of the GoPro custom adjustable bracket mount. In order to use the eBay suction cup mount, you need to buy the GoPro tripod adapter. I ordered the GoPro tripod adapter for $6 from Amazon.com and I ordered one of these eBay suction mounts. Total cost? $12! I did pad the order above $25 in order to get free shipping from Amazon, but that was not an issue since I bought a GoPro Bike Mount for $20 at the same time.