I looked at some vendors/suppliers both in Polska and the Uk, seems the expense is high, but probably not so bad spread out over time.
I stumbled across this site on my net travels, maybe you can tell me whether it looks like sells quality gear for good prices or not?
http://www.historical-uniforms.com/
How many times during a year does the group meet as standard? And also how is it managed considering people live all in different places?