Often your council can provide you with resources for free
  or inexpensive uniform parts.

  There is also a Web page that a Scouter has put together
called C.U.B.
The simple aim of the C.U.B. is to route uniforms from people who have
them and don't need them anymore, to people who don't have them and do
need them! This way, uniforms may be acquired for free (or almost
free) or via an exchange with another Scout or group. Ideally, the
only cost involved is the cost of postage.  C.U.B. can be located at:

http://www.globalserve.net/~codyak/CUBCodyAK.htm