Following mingofmongo's post on the LittleBits Korg Synth Kit, I've been on the lookout for more of these kits. Looks like JB has a bunch of them on discount, with the basic (but still cool) ones starting from $15 (were $79). Unfortunately, most are for click and collect (no shipping) but it might be worth trying your luck at your local JB even if click and collect is not offered. JB Hi-Fi in Blacktown still had a couple of kits over the weekend.
Also available is the Avengers Hero Inventor Kit for $69, which seems like a pretty good price, based on pricing at other stores.