When my seven year old son asked me for Pokémon cards, I thought nothing of it when I promised them to him, but then only to realise a pack would cost me around £5 and the collector tin would set me back by £13.
Yikes - I wasn't expecting that. And of course, my budding collector didn't intend to stop at one pack.
I purchased him a pack as it was a promise, and the tin would be part of a Christmas gift.
He was fine with that, but a week later and a growing passion for Pokémon, he wanted more and it turned into a daily nag of "want want want".
With that price tag attached to it, I told my son it wasn't something he could have every week.
I kept my cool - like many young children, my son is still learning about the value of money, and until he gets it, I'll just learn to live with being the worst mummy in the world.
But I'm not just ignoring his constant requests and instead I'm taking the opportunity to teach him about money.
We seem to go out of our way to make sure our children learn good hygiene, good manners, or how to stay safe, but avoid talking about money.
Some parents would rather talk about sex than talk about money.
"It's a ghastly subject," described one mum. "My children don't need to know about money, that's for the adults to deal with," said another.
Is money really that much of a dirty subject? I don't think it is and it's time to open up and face reality - children need to know about money because they will need it to survive when they are older and unless we give them the skills to do it properly, we are building generation skint.
A recent study by the Money Advice Service found that 32% of 16-17 year olds didn't have experience of putting money into a bank account, 39% said they didn't have a current account at all and a shocking 59% couldn't read a pay slip.
Another report by the Financial Services Compensation Scheme (FSCS) found that more than a quarter of children under age 12 had no experience at all with money.
You may think that's not a big deal, but financial education should start as young as age four.
Without financial education, children will not have the necessary skills they need to manage money in adulthood.
You don't have to get all serious and formal, just start early and then build on it as they get older.
Millions of adults in the UK today are struggling with money; many of which admit they don't know how to manage money and no one had given them the valuable lesson of budgeting, saving or even investing.
They speak with regret and wish financial education had been on the agenda for them when they were children.
But as parents today, we still have the chance to fix that and prevent another generation of skint growing up.
Don't worry about having specialist knowledge, it's the simple things that matter, like being open about how much you earn, showing them coins, giving them consistent pocket money and maybe even paying them for certain chores.
Let them see your pay slips and if you're in debt, let them know it. Like most important lessons, teaching children about money must start at home.
In case you're wondering how I dealt with my son's requests for more Pokémon cards, I told him he was allowed use his pocket money as he pleased.
He gets £2 a week and I told him that if he managed to save £20 without spending any money at all, I would double it. He hasn't touched a penny, yet.
Video: Top tips on how to teach you children about money with FSCS.
This blog first appeared on MummyMoneyMatters.com