Curry Cafe. Cheap, tasty, friendly. Three curries and rice for £3. Can't recommend it enough.
3 Soap Street, in northern quarter, behind Arndale, down a little lane. Half the fun is finding it!
Tel: 0161 832 4971
Updates
The price is no longer £3, but with a chapathi included for just under a fiver excellent value and one of the best authentic curries out there.
Is this your business?