Dollar store carpets.

Dollar store carpets are your best bet for marking important spots like the top of the stairs or any danger spots in your home.  They are also great markers for go-to places like just inside your exit doors, so that your dog can go to those places when he/she needs to go outside for a pee or when you come home.  I like having a mat to send my dog to wait on while I take my boots off and hang my coat up.  That way, no on trips over the dog because he is safely waiting out of the way.  He also stands on that mat and gives me a bark when he needs to go outside.