A quick google search pulled up this webpage:
It's not an outdated page either. You can access it directly from the main Home Depot main webpage by doing the following:
1. Go to http://homedepot.com
2. Click on "Company Info" [at bottom of homepage]
3. Click on "About the Home Depot" [on the left hand side]
4. Click on "About Our Products" [on the left hand side}
Home Depot PM policy
"What is your low price guarantee?
The Home Depot guarantees low prices on everything we carry. If you should find a lower price from a legitimate, local competitor on an identical item we stock, even if it's an "advertised special," we'll not only meet that price, we'll beat it by 10% to thank you for bringing it to our attention. To receive your discount, please contact your local Home Depot. (This guarantee excludes closeouts, liquidations, and clearance items).
If you find a lower price from a competitor on the Internet on an identical item we stock, please print the product/item page (including applicable taxes and shipping) and take it to your local Home Depot for verification. We'll be glad to match the Internet price. (This guarantee excludes closeouts, liquidations, and clearance items).