One of the most popular things to do for someone who could hop back in time a short distance has surely got to be throwing a bit of money at Bitcoin to become a future rich person.
Back when it started, the cryptocurrency was worth peanuts, to the point that one man traded 10,000 of them for two pizzas worth £25, a transaction which these days would have been worth hundreds of millions.
The pizzas had better have been exceptional.
If anyone chucked their money at Bitcoin 15 years ago and managed to cling onto their investment for all this time, then they'd be worth a lot of money.
Assuming, of course, that you still remember how to access your old Bitcoin and they weren't thrown away by accident, or you haven't forgotten your password and risk losing access to them forever.
They started out worth almost nothing (YASIN AKGUL/AFP via Getty Images) As for how much you, as this hypothetical time traveller, could make if you whooshed yourself back 15 years, Bankrate says if you'd put $1,000 into Bitcoin back in 2010, then you'd be sitting on something worth a whopping $1.62 billion (£1.21 billion).
That's a lot of f**king money for basically anyone, and all you needed to do was buy a grand's worth of something you had no guarantee would ever be worth it.
It's easy to say in hindsight you should have put some money into Bitcoin back when it was worth almost nothing, but in those days, you were putting tangible money into something which was initially worth so little that a few pennies of lost value would have essentially wiped your investment.
Bitcoin is also one of those things where getting invested early on would have been the important bit.
Bankrate crunched the numbers and said if you'd put the same amount of money into it 10 years ago instead of 15, then the value of your investment would have dropped from $1.62 billion to around $497,000 (£372,000).
Should've, would've, could've (Getty Stock Photo) The cryptocurrency didn't get beyond the value of pennies and cents until 2011, after which time it steadily climbed, and the thing you could have bought for the price of a Freddo ended up becoming something that'd set you back the cost of a holiday or a car.
If you hopped on the gravy train five years ago, then you'd have just under $10,000, which still sounds pretty decent to someone who doesn't do much investing.
The difference really is from that time when you could have made astronomical sums of money compared to what you'd get out of it these days.
Anyhow, it's time to go back to imagining what you'd buy with all that money you don't have.