You can get a
1000D with 18-55mm kit lens for under £350, which would leave you enough for a camera bag and memory card. They're good cameras with plenty of features and good quality results. The lens is what you will out grow more quickly and you might want to begin saving for a replacement or additional lens as soon as you can - a 50mm f/1.8 will set you back £85 from Amazon, Jessops or John Lewis.
Alternatively, you could go straight for the 50mm f/1.8 instead of a kit lens and get the 1000D for £299 (Jessops) plus £85 for the lens, and enough left over for a memory card.