There are lots of ways to accumulate bitcoin or start from scratch. Bitcoin has big plus that you can start with as low as 1$ and there is no upper limit also. But to me the key factor in Bitcoin investment is consistency, even if you are investing 50$/100$ per week make sure you do it with consistency. There might be times when someone will have extra cash and he can invest more at that time. Such strategy will help people with low cash in getting good amount of Bitcoin (or your desired number of Satoshis/Bitcoin) over a period of time. Our first and foremost target should be to get our desired number of Satoshis/Bitcoin and then we can adjust our investment accordingly.
To be a bit more realistic I think 1$ might not be feasible at certain times and it depends on what you would have to give away, like KYC data to an exchange. For those who want to keep it in a self-custodial wallet, 1$ investments would not be a great choice as fees would often times be a huge setback to someone trying to build a portfolio. If a good exchange is available, building a small bitcoin investment over time could be a good alternative. It's probably better if they keep some cash up to a minimum amount that makes the transaction be worth it and then buy some. 50$/100$ as you mentioned is a whole different story.
The parameters to determine the right amount of bitcoin that someone aims for could also vary over time. It depends on how the ecosystem develops and whether someone is able to improve their own financial situation, which would in turn lead to more potential investments into bitcoin.
I remember the times when faucets actually paid quite a lot. Back then nobody would have thought that using faucets would make any sense one fay. If someone constantly used those faucets from 10 years ago, it would have already paid off but I guess only a minority of people would have resisted selling those bitcoin when the first significant ATHs were reached. But once again the saying a penny saved is a penny got holds true here. Better start somewhere even if it seems to be negligible.