2. Help them set up a good savings account
Teenagers are too old for piggy banks - they need a proper bank account to deposit their savings in. Help them open one up - if they're under 16 then they'll be able to open a children's bank account. Once over 16, they can open an ISA which is a tax free savings account. They can save up to £5,340 in an ISA, but if they withdraw money it can't be redeposited.