How do you get extra money on moshimonsters

go to the port click on the rox trees (members only) by doing the daily chalenge. (hint) if you do the daily chalenge early in the morning and then come back at like 3pm you can do it again it worked for me!!
The above reply does sometimes work, but its just a bug in it. I collected port rox three times in one day once, but never happened again!