You could
A.) Make it yourself. Buying the type of fur you want isn't much of a hassle and there are plenty of guides around the internet on how to make tails, ears, etc.
B.) Commission someone else to make it for you. While it may be a little difficult to find someone to make the gear for you, you can find high quality pieces for fairly cheap. I got my first tail commissioned for only $20 with really good quality.
C.) If you have a local costume shop of some sorts, you might be able to have some luck finding some furry gear there. However, depending on where you're located, the chance of finding some there may vary, so visiting many different costume shops might be necessary.
Hope this helps and good luck to you