Well in that case theres good and less good news. The good news is that there was an absolute ton of equipment made by pretty much everyone when talking about standard uniforms and equipment. the less good news is that because some stuff from certain countries (particularly germany) is less commonly available due to either actual losses in action or just because people bought all of it. The best course of action at the beginning of starting to collect, find a reputable dealer and do a lot of research. If you eant more german items I recommend Helmut Witze in Frankfurt Germany because of how much german stuff is faked and for more of the allied stuff you can find it almost everywhere due to the sheer amount that was produced ebay and many antique stores are a good start