Indeed, a useful price range will be handy.
If you have around £150, I'd suggest trying to find a 9827R (which you can get on www.caraudiodirect.co.uk
for £149.99) I have one of these and it's done me proud. You may be able to find one cheaper second hand (which is always wise with car audio equipment)
If you have less than that, maybe try for a 984X series. They start at around £100 and go up from there.
If you want cheaper than that, you'll have to go second hand or ebay...
My 9827RR will possibly be up for sale soon, as I'm upgrading to a 9853R...but I'm not sure yet.