I think it's the best time to invest in Bitcoins (if you see it as a safe-haven asset and are interested in much better gains than keeping your money in banks). I won't ask you to put too much, but for an average person - I believe that $500 shouldn't be a big deal to invest as the risk-to-reward ratio here will be much higher compared to other assets available.
Best time to invest is if you bought the dip... Though right now is still a decent time to bet on BTC going up long term.
I really do think that markets have matured enough, and that we're probably never going to see BTC under $5k again any time soon.
The pullback was really expected, but the dump got the weak hands going absolutely bananas. People posting about why BTC will go down to $20, even. That kind of thing happens when BTC is crashing, but never happens when BTC is rising up.
Don't trade with your emotions, because after a dump will always be a pullback, and that is now.