I regret leaving bitcoin; last time 1Bitcoin cost like $600 now look where it is now; i would've made a really good investment. I only had like 0.5Btc in my account; im glad it gained value but i know i could've earned so much more if i stayed
You are not alone in your regrets
Many people sold their bitcoins when the price had just started to rise from its long-term lows at or slightly above 200 dollars per coin (if that comforts you somehow). Buying Bitcoin right now might seem not to be a very good idea overall, though I remember perfectly well when folks were telling exactly the same in last November when the price had first reached 800 dollars after so many years. Nevertheless, you can always earn bitcoins directly by doing different jobs. Participating in a signature campaign is the easiest (but you should know that already)