Make a save and then go to the gambling website and play blackjack and bet everything you have and if you win then repeat and repeat and you should make a lot of money. Oh and if you lose then load up the save you made before gambling.
Buy stocks on Day 5 around 19:00 or anytime it's gone cheap (ideally when it hit rock bottom), so check stonks regularly. Typically these stocks will skyrocket in a day or so, giving you a huge profit (I just got 100k on day 5).
You can go gambling sooner by typing casino.ic in the browser bar. I play blackjack until I hit the max amount I can bet (100,000 token I think). By day 5 I had 4 limbs for my bots and enough money to buy a ton of stonks when one hit low.