TER is not hugely popular in Portland, but since you are on here already, you should use their ad board and take advantage of the free once a week ad.

You can use eros. If you are a p411 or Date-check member, use them for advertising too. There's always Backpage, but be careful how you use it if you choose to use that site.  There are a couple other sites that are poular in Portland. They post ads but also have reviews so they can't be mentioned on ter, but you can probably find them by googling.