i send a monthly mailing to my friend Nita. In another life we worked together and I ran the advertising department and she ran the credit department and our company lived by our weekly mailings. It had sales figures, that week's ad, signing info, etc. So now I send her a much more fun monthly packet of stuff. It usually includes a paperback, a letter and I know she likes stationary so I try to include something.
I recently ordered these little one page scalloped cards from Paper Source.
I had nice colored envelopes from my card making so I lettered her name at the top of the cards and added a colored envelope and volia, you are done! If you don't have mad lettering skills you could stamp something or make a little collage, whatever strikes your fancy. Envelopes also come from Paper Source and are of a nice quality. That is good because Nita only likes nice things.