Oh, you're right. Although 50% per year is still insane.
And I definitely forgot about investing, but also didn't account for inflation, which maybe would cancel e/o out.
Doesn't really matter if you consider the difference between a million and a billion is roughly a billion.
In Germany, and by extension the EU, we have a website called "geizhals", which basically translates to "penny-pincher".
It is an insanly good tool to find the specific item you're looking for and where to buy it for the least amount of money. Its got a pretty robust search, and some of the most comprehensive filters I've ever seen. When I cant find what I'm looking for using Amazons search, which is nearly always, I use their site instead.
Only real downside (for me) is when stuff isn't listed on there. They probably collect data and stuff, but they also provide a useful service in return.
While writing this I have also noticed that they offer the same thing called "skintflint" for the UK. Maybe something similar exists for ppl. in the U.S. ?