What's a cheap, yet meaningful gift I can buy my friend to let her know I'm sorry for sleeping w/her husband?

If you're the kind of girl I think you are, you saved the boxes that all those crotchless panties came in that your boyfriend bought for you. Remember that he'll get bored if he sees you in the same underwear all the time so just pick up those old panties off the floor and put them back in the box and re-gift them to her! Hope this helps...