LucyCollie wrote:
I strongly recommend http://www.dogbooties.com/ . They make gear for sled dogs so their dog booties are tough & easy to put on yet extremely reasonable in price. My smoothies have worn booties from them since the mid-90s.

(edited to correct grammar)
^ I second this company. We use these booties on our sled dogs. They are so cheap, so we just replace them when they get worn out.