It depends if you want to stick with TY or not.
Either way, check out svp.co.uk.
I bought a tub of 100 unbranded TY -R's from them last week (TYG02) for 30 quid, great service too.
They send around four e-mails letting you know what's going on at each stage of your order (card transactions, picking packing etc), and the stuff's quite well packed.
As for other brands/MIDs to try, MBIPG101R04 sold as Imation or TDK 8x +R -which I believe Francksoy and Arachne are bigging up at the mo.
Verbatim 8x and 16x are usualy good bets too as long as they aren't described as "Pearl White". As JayC30 says most pearl white is Ritek. I've had a 25 pack of these containing CMC MAG AE1 but real MCC is preferable to either IMO
I'm hesitant to recomend any CMC manufactured discs without knowing what burner(s) you're using but my BenQ burns these with surprisingly good results, even their Double Layer discs!