To start, you'll need to do some thrift shopping. In her video, @BrookeDarwin uses a porcelain doll, which are pretty expensive if you buy them brand new. However, I was able to find tons of options at my local thrift store for around $5. You really want to avoid plastic dolls since they aren't as durable as porcelain. As for the other materials, you can find acetone-based nail polish remover, potting soil, and moss at your local department or hardware store.