I played this game for ages, wondering why everything took so long. I had planned on posting a message saying that a future update should make it take not so long to earn money. But I finally found the prestige button hidden away in the shop status box in the top left.

Once I reset one time, it took me 7 minutes to buy everything with a x7 bonus.

And there is a bit of an error with the prestige system as I discovered playing the game again as the save game doesn't seem to save.

When you prestige, the number of new loyal customers is VISUALLY affected by the bonus, but in reality the number you see needs to be divided by your multiplier to calculate how many new customers you actually have. 

For example I have 270 customers with a x28 bonus. I have have 7023 new customers with a x24 bonus. 7023/28=250 which is the actual number of new customers and explains why the new bonus is lower than the current one.

Seems that the way to really kill this game is not to prestige at all. I just kept the game running for about 12 hours and maxed out everything without selling the shop. That got me a prestige bonus of over x1500. After that the game took about a minute to finish.

I will leave the game going  now, earning a billion every 3.5 seconds. I want to see if the money goes to minus when it hits 2.14 trillion.