How to box LP's

I plan to sell some LP's pretty soon. Some one at a time, some in small groups - 3 to 10 - and a few in larger groups. Do any of you know where I can get appropriate boxes to ship these varying numbers of LP's?
Thank you.
The Sleeve City record mailers and pads work well and are reasonably priced.
Also check out the "media rate" at the post office
Just one extra comment. With Summer approaching, remember US Postal Media rate also means items sitting in boxcars for long periods, Long and hot enough to start melting LPs.
Depending on the weather, you might suggest to buyers to opt for 2day air. I have gotten LPs from the West with a flat on the edge and 2/3 of the grooves.destroyed from heat.
Just a heads up.
You can realistically dumpster dive for corrugated cardboard and just duct tape together your own boxes. If that isn't classy enough for you, the art supply store of any art school has sheets of new corrugated cardboard. As long as you have sufficient density, it should survive the transport.
Looks great, thanks for the tips. Boxes found :)

I wonder if even 2 day Fed Ex would avoid the heat problem during the summer?
cut up free fedex boxes to make your bozes!