This is a question with lots of different answers, depending on who you ask. Some argue that shopping for a motorhome is like buying a car. The high season for buying a car is April — September. So theoretically, any time in October — March should count as the best month to buy a used motorhome. And therefore increase your chances of getting a bargain.
But a lot of people will tell you that there is no “best time”. And that you can get a bargain at any time of the year.