"How do we decide that the price of an asset is low?"

One great way to determine this is by using a momentum technical indicator called RSI (relative strength index). When RSI is above 60, it is considered overbought and may be time to take profit. When the RSI is below 30, it may be time to start buying in. It all depends on the scale you use (days, weeks, months).

You might be wondering: "So what can I buy that shows an oversold RSI currently?"

I'd be glad to show you!

Bitcoin just bounced from 30 up to 40 RSI (daily chart)
In most cases when Bitcoin has hit 30, it has made moves higher, I am personally waiting for trend confirmation.

The Dollar (DXY) just hit a low long term RSI level and has moved up to 50.
Moving your capital into the dollar all depends on where you think assets are heading. Are we going to see a bit of deflation? or will they continue to head higher. The dollar moves opposite of assets.