Let’s say you come upon a time machine that will take you to any point in history, no going forward or taking the machine with you. So if you could go back and take one piece of technology with you to earn your living what would it be? Example take a modern computer to the 1960s and rent time on it to NASA.
Information is far more valuable than any piece of technology. So the technology I’d take back would be a 3-ring binder, containing things like stock prices, winning lottery numbers, technical information on various inventions, etc. (Of course a laptop or tablet could carry far more information, but then I’d lose it all if it breaks.)
An interesting question is what the most lucrative and dependable information is. The moment you show up in the past and the time stream starts changing all of your lottery numbers, stock tips, and winners-of-sporting-events might change.
So maybe locations of recently discovered mineral strikes, shipwrecks, and things of that sort? Look for any of those “this family discovered an original copy of the declaration of independence at a garage sale” stories, and research the details so that you can swoop in ahead of time.
For pure profit, and no particular desire to disrupt the time stream, information is still the way to go. Here’s your chance to get in on the ground floor of Apple, Microsoft, Google, etc. You can ride the tech stock boom of the 90s and bail just before the bottom drops out. Use sports results to raise a stake in Vegas, then invest and wait.