I've been looking also (mainly for cheap lemon essential oil as I don't want to spend heaps for this purpose). I got some citronella oil and put some on a rag and rubbed it on my broom while I swept around my light fitting, door, window, built in robe, cornises and the floor of my bedroom and since then I haven't seen any spiders in my bedroom. Yet to do the whole house though.

Also haven't had any flies of mossies in my bedroom either!