Sandisk 8GB Micro SDHC card for £8.99 from Amazon. I think it's a decent price for a branded 8GB SDHC card.
This has been falling in price for a couple of days now; was £9.45, then £9.15, now just £8.99. Select the 'Frustration Free Packaging' option to buy at this price.
I've been looking at SDHC Micro cards since I bought my new mobile a week ago, I actually ordered this exact same card off Play.com for £9.49 yesterday because Amazon estimates delivery in 2-4 weeks. Still, a bargain if you're prepared to wait a bit!