Ok biz, I'm trying to retire in twenty years, should I invest

If you're willing to wait, you should go for the lower risk option.

>>2913847
I'd go for low cost mutual funds

>>2913847
Mutual funds

Why not both?

Forget penny stocks for saving for retirement, those are only good for trading / gambling.

For long term investing for retirement you'll probably want to put 70% in index funds covering all of the following:
small, mid, large cap
value and growth
international / domestic, most domestic
then smaller amount of REIT, emerging markets

Then put 30% in crypto currencies:
50% bitcoin
20% eth
and 30% on litecoin, ripple, dash, spread it around the top currencies

>>2913847
Twenty years is long enoughto do something between those two extremes, go for small/midcap growth stocks, do some research, you can either hold for longer than a year and one day to get the best taxes or set buy/sell orders to buy dips and sell surges, you can do this on larger cap stocks too, some of your money should be in REITS or dividend paying blue chip stocks, bonds are unnecessary and if you want to mess with internationals or gold/commodities that's your business. But a longer version of Swing Trading is much more reliable than day trading and penny stocks are garbage, while indexes will lead to a nice, noworry profit, for a little more effort your compounded gains vs buy and hold index could be huge. Note that holding a concentrated amount of better stocks yields better results, the risk if they might go down but in twenty years they are almost bound to gain.