The best I could do was OfficeDepot, who has cool cardboard ones for about 50 cents each:
Cardboard CD mailers. If I order some pens or something, I can get free next-day shipping to their destination.

The cardboard ones are good because they protect the jewel case.

My experience with transferring funds to the US is not good, so it has to be a place where I can use Paypal or my “cards of power.”

See here.

There are a bunch of them here.

For a real store: Link

This is o.28 cent each. 50 minimum. I asked them about creditcard payment and this what they say: “Alison Rosin: If your billing address is listed in Europe, you would have to do the wire transfer”. Also “Alison Rosin: We would be happy to ship your order to a freight forwarder in the U.S.A so that they may forward your order to you. Uline is not able to ship internationally at this time.
Should your billing address be outside the U.S.A., please understand that we do request payment in advance with an electronic funds transfer.
”
They don’t accept paypal. I don’t know if you are willing to do the funds transfer or not since fees usually apply.

Link

There are a bunch of them :http://search.ebay.com/cd-mailer_W0QQ_trksidZm37QQfromZR40

For a real store:

http://www.uline.com/Browse_Listing_1451.asp?desc=Jewel+Case+%2D+Corrugated

This is o.28 cent each. 50 minimum. I asked them about creditcard payment and this what they say: “Alison Rosin: If your billing address is listed in Europe, you would have to do the wire transfer”. Also “Alison Rosin: We would be happy to ship your order to a freight forwarder in the U.S.A so that they may forward your order to you. Uline is not able to ship internationally at this time.
Should your billing address be outside the U.S.A., please understand that we do request payment in advance with an electronic funds transfer.
”
They don’t accept paypal. I don’t know if you are willing to do the funds transfer or not since fees usually apply.

http://www.uline.com/Browse_Listing_1451.asp?desc=Jewel+Case+%2D+Corrugated