A call has made for an end to the "pocket money" price of shop-bought alcohol fuelling under-age drinking.
Alcohol Concern Cymru said shop deals mean the weekly recommended alcohol limit for a man can be bought for less than £4 and a woman's for under £3.
It backs Welsh Assembly Government ministers' bid for power on alcohol licensing and pricing.
The charity said it wanted to see the unit price of alcohol raised to 50p as a way of deterring under-age drinking.
Andrew Misell, the charity's policy manager, said the "ludicrously cheap" price of alcohol saw it on sale in some places for the equivalent of 18p a unit.
He said: "If you take those low prices and you have retailers who are willing to turn a blind eye to underage purchases, then alcohol becomes available for young people.
"This is why we talk about "pocket money" prices. The issue with young people is that they tend to have less money. They may still be in education.
"If you are making alcohol available at such low prices, then young people may be able to get together enough money to buy a couple of litres of strong cider.
"You can get pretty drunk on that."
The charity said its research had found some 500 under 16s in Wales were admitted to hospital for alcohol-related problems annually, while 54% of 15-year-old boys and 52% of girls have been drunk at least twice.
The charity's report highlighted the alcohol-related harm reduction strategies used in Cardiff - based on work by hospital surgeon Professor Jonathan Shepherd - which researchers claim has made the Welsh capital the safest city of its size in the UK.
Tony Jewell, Wales' chief medical officer, has called for Welsh ministers to have powers to be able to introduce tougher controls on alcohol to tackle "the binge drinking culture".
Dr Jewell said alcohol was "extremely cheap" compared to 30 years ago.
Mr Misell said the charity welcomed the idea of the assembly government having such powers.
He said: "This is a chance for Wales to lead the way.
"There is not the push from Westminster for a minimum price when there certainly is from the assembly government."
Consultant paediatrician Dr Heather Payne said the annual figures for under age drinking were happening everywhere.
She told BBC Radio Wales: "We have to do something it's an epidemic and it is destroying certain aspects of our society. It's destroying the future for some of our kids.
"I think the problem is that people see the dangers of alcohol as being too remote. They're not.
"The dangers are immediate, not just in the future, where we are seeing young people in their twenties dying from liver failure...so its poisonous."