Molds can be made out of playdough, plastilene or even the metal bands used for strapping boxes to pallets. You can even use plaster of paris if the piece is not going to be eaten. Silicone molds and making them are great if you can afford them another site is www.chefrubber.com
I think they carry them as well. Trick is do not let your imagination be limited to just what is available on the market. Metal cookie cutters can be used, cake tins make great bases for sugar pieces. Even heard of people using the rubber tubing like goes on blood pressure cuffs not sure how they did that. When working with pulled sugar,blown sugar or casting pieces just let your fingers and imagination take you where they may.This art is not something you learn overnight if it was everybody would be doing it.