Investing $100 in Bitcoin is a good place to start, at today's price of $21802/BTC will give you 0.0046 btc. The way I see it, don't focus on thre dollar value but rather be focused on the amount of bitcoins you have stacked. You get a good feeling when you hodl a good amount of bitcoins. Buying today is a good investment because you would be buying dip should Bitcoin price fall down further you can still buy more and hodl