Hi Lori,
What size stake are you looking for? How tall?
I once bought stakes from an online nusery supply house, but I'll have to check to find its name..back then, prices were reasonable. 3-4 yrs ago.
Is there a particular material you're looking for? They come in plastic, wood, moss and that brittle stuff. Because I needed a huge stake a yr ago I went to Home Depot and bought a long, round pole..They sell 10' and longer at a local nursery, so I ended up getting 2, then cut one to fit the plants I needed standing.
If you decide to go w/a tree trunk, find the strongest, straightest piece available..then, be sure to clean it thoroughly..W/soap and/or bleach..Tiny bugs live under bark, you'd be surprised the little critters that make homes in branches..but it can be done..Remove any leaves or sharp side stems growing off each piece of wood. Good luck, Toni