I had solely used Lexar cards for a while but one day needed a card in a hurry so bought a 4GB Peak card from Novatech for £7. Sure, it doesnt write as fast as the 1GB Lexar cards (which were £34 a pop!) I have but other than that its been bulletproof.
I think the main difference between the cheaper cards and the more expensive ones are the write speed, but if you dont need to shoot 6fps or above you should be fine!