Vicky Mitchell, 42, and her partner of 18 years, Adam Fry, 38, joked their only car-buying plans are limited to a new Skoda Citigo after scooping the equivalent of a £200,000-a-year salary, guaranteed until they are pensioners.
Speaking at a press conference near their home in Halifax, West Yorkshire, Ms Mitchell said she is hoping to travel to European cities, including Budapest, but is not cancelling her plans for caravanning in Skegness next year, saying: "You can't beat a caravan holiday with the kids. They love it. We've already booked for next year."
The part-time admin assistant at an accountancy firm said the current household income is under £30,000 a year and the win will give financial security to her two sons, aged eight and 19.
Mr Fry said he will to continue to account for every penny of the family finances on his three-month rolling spreadsheet but admitted the top prize win on the National Lottery's Set For Life game will mean he can pay off family debts.
The pair said they both plan to keep working and definitely have no plans to marry.
Mr Fry said the current family car is a 14-year-old Vauxhall Agila, which is "falling to bits".
Ms Mitchell said they had already looked into buying a car.
She said: "I Googled 'best family car' and Skoda came up as best family car. So, I've seen a little one that'll be enough for me."
The couple said they are also thinking of moving from their two-bed terrace to a bigger property but would have to save up for a deposit first and they are celebrating with a pre-booked holiday to Ibiza.
Ms Mitchell explained how the win was her third lottery win in a week.
She said she played online as she was heading to Skegness for a break with her younger son.
Having won £10 on the Thunderball draw, she re-invested the cash and won £5 five days later on the Set for Life game.
When she re-invested that win, she hit the jackpot when she played with the last £1.50 left in her online account to buy a line for the August 12 draw.
Her lucky dip winning numbers were 03, 20, 26, 27, 32 and the life ball 05.
She said: "In a million years you never think you'll win big but this is life-changing."
Mr Fry recalled how he was woken up by his partner early in the morning after she received an email telling her that she had won.
But he said he went back to sleep because he did not believe her.
Ms Mitchell said: "I was half asleep when I saw the email and thought 'great it's another fiver'. I couldn't work it out and see what I had actually won. It said I had to log on."
She added: "It's still sinking in but whereas before I would see a jumper for one of my sons and think that I couldn't afford it, I can now just buy it."