1) Yes I believe it's a putty knife, but I would recommend using a plastic scraper and see how you like it before using the putty knife.
2) If you're looking for a cheap brush I find them at dollartree store: Dollar Tree, Inc.: Search Results on brush
try to find the stiffest brush would work best.
3) I myself use around 26 grams or an ounce of wax for each snowboard but I've read it can be cut down to 12 grams for each wax. So for me a pound of wax would last me around 16 wax jobs.
Hope this helps