Pool Nation FX

To get this achievement, you must have 100,000 dollars on you. Do not spend your money in the store, or your progress will go down.

An easy way is winning the 9-pool tour on Hard difficulty, with novice aim. By the end you would have 97,020 dollars. Just play the bonus matches for the 2,980 remaining. This will get you this achievement, plus beating 9-ball tour, and 9-ball tour on hard achievements. After getting the achievement, spend it all, earning you the Hey Big Spender achievement.

Note: Use the replay glitch while playing the tour to speed things up.

Update - May not work since recent patches as I have no way to check

If you go to Play for Cash matches you can start at the lowest entry fee and trade off forfeiting with a boosting partner (it didn't seem like there were many people searching but make sure you both start searching at the same time.) and you should each slowly increase in money. Once you have double the entry fee of a higher tier you can move up the bets. Just make sure to trade off forfeits so you both always have enough money to enter. Credit to Hurricane Ham who helped discover this method