I think Sports Direct need applauding for making cricket affordable, I bought my two this and the next 2 years trousers at £3.50 each.
For personal items I really do think advice should be sought, every kid wants a bigger bat, it really throws juniors when I tell them that my bats are made slightly smaller (as I am not 6 foot tall).
Is it as simple as measure the distance from floor to hand when held by the side - that way differences in manufacturers sizes are ruled out??
After that it is all down to the stickers
Maybe just maybe there is an opportunity for the forum to create a hand me down section, with set rules such as a size 3 that is in decent nick is bought for a third of the price, so you can buy a bat for 45 and sell it on for 15? The only down side is postage costs