I don't know if you have a Hobby Lobby in your neck of the woods, but I've found some great plastic plants at awesome prices there. Usually they have a 50% off sale, so instead of $3.50 for one bunch you get it for $1.75. I don't know about the silk ones, I wouldn't trust those, but I know the plastic ones are safe to use. They usually have very long stems so I just bend them at a right angle and shove them under the substrate...works just fine to anchor them.