Need inexpensive outdoor storage in Portland, Oregon

We are in small town Western Idaho and pay $68/month for a covered pull through space for our TT (30' overall) plus room for two four wheelers at the back of the trailer. It is in a secure storage area with a second locked gate entry into the area where we park. I see several lots in this area with open storage, but I don't think that even those would have a space for $25/month.