I would like to recommend these American Apparel nail polishes. There is a shop in Liverpool, for some reason they are only £7 each and 3 for £17 which is quite reasonable! Also, one of the colours I picked, Palm Springs (a nude one) is being discontinued so it was only £3.50! Four new polishes for £20.50, pretty good deal I thought!
I haven't used all of them yet, but the colours are opaque in one coat (I still do two out of habit) and the gold leaf type one is so pretty. Can't wait to do gradient nails tomorrow!