(We're a part of a huge interfaith family so we celebrate both holidays - yaaay me!)
I found two shadow boxes at Michaels on sale for $15 each.
I used numerous textured scrapbooking papers (although my crappy camera doesn't really show it in detail) for the tree trunk and the leaves. My total for supplies was approximately $35.
I also left a few spaces open for future additions to the family and I'm hoping to do more research in order to add more ancesters. Overall, it was a fun project to put together and hopefully it will be a nice conversation piece in their home.
I definitely can't take the credit for the idea. I was inspired by this beautiful family tree from red envelope, but I didn't want to shell out the moola for a kit I knew I could probably make myself.