A Jewish camp normally offers a price of $2000 per child per half or $3500 for the whole summer. Normally by the end of March, the camp fills us completely, but this year it is only 65% full. To achieve max capacity the camp offers a discount of $1800 per half or $3150 for the whole summer. Is it permitted to do this?

ב"ה Shalom What I understand is that you are merely offering a discount price. According to the Shulchan Aruch, (חושן משפט הלכות אונאה ומקח טעות סימן רכח סעיף יח) one may offer incentives or discounts so that clients buy from him or in your case sign up for camp. All the best