it depends on how you are going to go. If you take 528 (north end of airport) the whole way I would say have $2.50 if you take 417 to 528 (south end) $3.00
DH and I aslo live in Oregon and did our first cruise in April this year. There are 3 tolls I know that 2 were 1.00 each and one was .75 cents. You do not need exact change the toll booth attendants will make change. You can check out this website as well www.expresswayauthority.com for the map.
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