In Noob Towers, up to 100 coins (200 with Double Coins gamepass) can be won per tower. In Pro towers, up to 250 coins (500 with Double Coins gamepass) can be won per tower.
Before, you could only get coins by winning a tower, but since the March 4th update, you can now earn coins by beating sections one at a time. You earn 2 coins (Noob Towers) or 1 coin (Pro Towers) by beating the first section and it will increase exponentially as you go up.
The amount of coins you've accumulated in the current tower is shown on the sidebar, next to a coins symbol and a bar showing your highest point. This change was received well, especially by players that aren’t the best at obbies.
If a player decided to add the "Lengthen" mutator, users won't be able to earn coins from the tower (both noob and pro) until after beating the second section.
You can get coins by winning a noob or pro tower, buying them with Robux, or purchasing the Membership which will give you 500 coins each day.