Bitcoin maybe cross 100k today, why are you thinking 500$ ? It's totally unemaginable. So calm and relax. See what are going on...
The chances of Bitcoin to 500$ is equally zero. If it happens the market will be flooded with largr investors that will buy all Bitcoin before it get to anyone.
Buying low is always an advantage, so i expect everyone who comes across Bitcoin at that price to buy more, but the possibility behind the imagination is far from reality. Where we see Bitcoin now is to hit $1million very soon.