Making that choice depends on the topic. There is a list of ecology journals here, ranked by various measure. http://www.scimagojr.com/journalrank.php?category=2303
If you click on the journal name, you get a journal page that describes the subject focus of the journal. From there, you will have to go to the journal homepage to see what the charges.
You can publish your paper in the Journal " TROPICAL ECOLOGY". It is a very good refereed journal and publishes papers free of cost. Please check the following link for details.
I suggest you to publish your research in Open Access journals. They do not charge anything for publication. Here I give a list of some quality open access journals in the field of ecology:
Ecosystem Services, Ecology and Society, Ecology and Evolution, EcoHealth, Environmental Management, International Journal of Ecology, Global Ecology and Conservation, American Journal of Environmental Sciences, etc.