Ecolodges and eco resorts are usually more affordable than regular ones because the employees are local people and volunteers. Of course, they also save a lot of money by conserving resources at the lodges. So you might end up having a much cheaper vacation at an ecolodge than you expected.
I'm not sure about all, but I think some ecolodges might have discounts or lower rates in return for volunteer time or help around the facilities. I don't know how many people would prefer to do that but there are really many options out there. So if you don't mind volunteering a few hours to get a cheaper stay, you can do that. If you prefer to pay full rates and really feel like a guest there, you can do that as well. Either way, I'm sure that it's going to be a fun and enjoyable time.