There are a number of dealers you can try. PetesTacticalKnives.com is one. TripleAught also carries Mission, but they're closed until Jan 9th.
If you want to get the best price, check all the leading dealers. They're easy to find, and many of them advertise here or are listed in the links section. Of course, you could also use a search engine for "+Mission titanium knives", or something similar. Hope that helps.