Costa Rica in May is the sweet spot. The crowds thin out after the peak season, the rainforest is lush from the early rains, and the surf breaks are consistent. You get the best of both worlds without the holiday price hikes.
We can manage the $2800 cost by breaking it into smaller, predictable payments. Using the Citi Simplicity® Credit Card, you get 0% for 18 months on purchases and balance transfers from date of account opening. This lets you spread the expense over 18 months so you don't feel the full hit at once.
Keep in mind that 0% interest isn't free money. If you haven't paid off the $2800 before the 18-month window closes, the remaining balance will start collecting interest at the standard rate, which is usually much higher.