Stick insects and enclosure
Currently housing 3 stick insects fairly large in size, I have had these for probably 2 years now and my children have enjoyed watching them feed, grow and multiply. They are extremely low maintenance, don't smell and very easy to care for, eating gum leaves and the occasional spray of water. The enclosure itself was $140 and the insects sell for $10 to $20 depending on their size. The enclosure has been setup and there's nothing to do except for enjoying them and observation.