Doug can be rented for the following periods of time:
7 Days/ Week-long Doug - 10 Daily Glowbucks
30 Days/ Month-long Doug - 15 Daily Glowbucks
90 Days/ Seasonal Doug - 20 Daily Glowbucks
365 Days/ Annual Doug - 25 Daily Glowbucks
If you purchase Doug, and move him to your storage the timer will still count down from day of purchase, even if he isn't in your forest - so log in and check on him everyday to collect your limited time rewards!