I know Home Depot sells Hampton Bay products, but they do not seem to have the replacement blades that fit Hampton Bay Models. Where can I find replacement blades?

I found Universal Blades at Home depot that work on different hole spacing.
If I remember, The Mounts and the blades sold separately.

Depends on the model of your fan. You may have to contact the manufacturer.

Ceiling fan replacement blades- Ceiling Fans N More (http://www.ceiling-fans-n-more.com/replacement-ceiling-fan-blades.php)