The country where I live (Pakistan), 100$ per week (or 400$ per month) is not a small amount. Here average income is around 300$ per month. I try my best to accumulate as much as I can but investing 100$ per week is not in my reach TBH. If you are from developed country like USA where average income is 8000$ for such people investing 100$ in Bitcoin or any other asset is not a big deal.
Rest I do agree that there can be resistance at 50 or 55k rather with current dip we can inferior that Bitcoin has its first resistance at 44/43k before it make its way to 50k.