I've sent 1000s. Can't recall any being damaged

I put a piece of cardboard, usually from a cereal box, in my SASE. This sometime prevents bending, but not always.

It really is better to just take your chances. I have gotten cards back damaged or creased a few times, but that's the way it goes. I have heard of people sending cards in toploaders and getting them back with the toploader -- not the card -- signed. So just send the card unprotected or put an index card or a piece of cardboard inside the return envelope if you want.

You could put "Do Not Bend" on the envelope and use cardboard, but I have never gotten back a damged card.

Yeah I just send them in a plain envelope with no protection at all. I have gotten a few hundred back with only one being damaged.

I've sent many trading cards to celebs through the mail in a plain envelope, and I've never had one come back bent or damaged.

I'm going to be sending a few trading cards through the mail...the cards themselves are not at all valuable and if they get lost in the mail, I won't be upset, but from a protection standpoint, to keep from bending, what might be the recommended way to send them? I use thick toploaders in my collection, but i'm afraid that it might rip open the envelope (we all know that the postal service isn't exactly gentle with anything). Any suggestions?