Hi Tim,
There are a large number of suppliers, but you might find your instructor has a relationship with someone local (as I do), so the first port of call is always them.
Most schools do their own t-shirts, so you know... and Kama aren't Bujinkan weapons... as with everything, take it one step at a time... you may find that your instructor has a preference for specific weapons at particular grades... or in a specific order... with my students, they are free to get any weapon at any time they want (in conjunction with discussing it with me... I'm not about to advise a shinken for a newebie, for instance), however there are specific recommendations and requirements at particular ranks... Hanbo first... then a Bokuto... training knife... and so on.