As has already been mentioned, you can't buy MTP unless it is second hand issue kit on ebay. The best you can do is get a similar multi terrain pattern pattern. For a long while this meant Crye Multicam but now everyone and their dog are producing variants. Vista ATP is one and Highlander MTC another.
By Bergan I assume you mean something similar to the current issue 125 Litre one? If so then I don't think there is that much decent choice - watch ebay and look out for issue ones!
If you want a large daysack and don't want uber top quality then I'd suggest some of the Highlander Pro-Force stuff is pretty good value. We sell the Tomahawk Elite SF Multicam one for £87.59 (minus 10% ARRSE discount!) which I think is a pretty good deal.