If you’re 18 today and saved the same $3 a day, by the time you’re 65, with the same 6% assumption, we’re up to $264,000.
Of course, if you’re 18, you’re thinking you’ll never be 65. But actually the chances are that you will be – with an an extra $264,000 after tax in today’s dollars in your Roth IRA, for being a bit frugal.
It’s cheating – but fun – to assume more than 6% above inflation, but it’s not impossible, either. So if we go wild and assume 7% instead, the $264,000 jumps to $360,000.
And remember, this is still just on $3. You could double that if you found a second way to save $3 a day – say by buying one fewer gallon of gas a day by (in the short run) driving more carefully and (in the long run) switching to a car that got better mileage.