Mike,
for patches you have to keep an eye out for different sales going on.
Keep looking at the sales thread/ detachment merch here on whitearmor.
Also there are sometimes some available on the 501st legion forum and your local garrison forums as well. Its just a matter of find when the runs are going on.
as far as compression gear. Just look through different websites. Underarmor makes some good ones that you can find. Also finding basic compression tops/bottoms on walmart, target, dicks, etc...
just look around.
there are also some that are sold within the forums as well.