Here are some really easy to make coordinating note card and envelope sets.
I used a kit that included quickpages (Secrets Of Nature by Manu available at scrapbookgraphics.com). I sized four of the quickpages down to 5″x5″, printed them onto white cardstock, trimmed to size, and then glued them to front of store-bought envelope. I’ll just write the person’s name/address in the part where the photo would normally be placed.
For the note cards I made a 5″x10″ canvas in my photo-editing program (Photoshop). I combined a few of the elements from the kit on the lower portion of the canvas (below the fold line). To make it easy, I kept the base graphic (the black swirl and the tree) the same on each card and just changed the one featured image on each card (flowers/butterfly). I printed each note card onto white cardstock, trimmed to size, and then folded each in half. That’s it, nice and simple!