I'm afraid We've never been able to finf a cheap one near the airport. We use The Hotel Airlines International, its a smallish hotel, not as grand as it sound. They pick you up and deliver you back, it's about 5-10 min. from the airport. Last time we paid about £40 or so. The web page I have is http://www.goldenswan.com Hope this helps.
alan

the link won't work unless you delete the space after www.

Link fixed. Thanks del949.

luci

hotel arma lake mumbai £12 a night and airport transfers a bit cheap maybe

There are quite a few recomendations in the Indian forum

Indain Forum link

Mids

thanks everyone