Everyone loves a great smelling home, but why pay an arm and a leg for it. Yes, I keep my house clean, but I like to have a plug-in here and there to make sure the house is on the up and up (esp. around the litter box). I bought the Frebreeze plug-ins, but the refills are $6...yup I am that cheap. So I took off the lids and filled them up myself with castor oil and orange oil. Total cost per refill: about 50-75cents.
It's simple...take off the lids, fill 80% with castor oil (or any other cheap carrier oil) and about 10 drops of any essential oil.
Boom! Your house smells good and you got your thrift on!