Hello!
You can buy premium bonds in blocks of 25, with each bond costing £1. The maximum you can hold is 50k.
Each bond is entered into the prize draw every month where you can win prizes from £25 to £1 million. As every single bond you own is entered it's possible to win multiple prizes in each month. Prizes can be automatically reinvested as bonds, or can be withdrawn to your bank account (for me this takes about 5 days after the draw).
You don't earn interest so premium bonds don't offer a guaranteed income, but they do offer a chance to win big! With small holdings you can go quite a while with no winnings which can be disheartening but every month we see people winning huge amounts on very small holdings, which gives everyone hope! 😂
You can cash your bonds in at any time with no fee however I imagine it'll take a few days for the money to reach your bank account.
I don't have experience holding bonds for anyone else but personally if you don't intend to buy your own bonds I'd just keep your sons in your name as it's more straightforward.
I love premium bonds, even though I'm not particularly lucky and haven't had great returns. I always get excited a few days before the draw and it's such a good feeling when you win a prize!
I think in your situation I'd leave the 5k in your son's account so he can benefit from the higher interest rates (unless you can find a better savings account), then maybe put anything above (for which you're only earning the lower interest rate) in premium bonds.
Obviously if you do choose premium bonds please come back and join us on the thread!