What is the cheapest way to travel between cruise ship terminal in vancouver bc to seattle, washington?

You said cheapest so here goes; Take public transit, yes public transit which costs a total of under $10 one way per person but requires several transfers. The sequence is as follows; Starting from Vancouver,BC take the Sky Train to Tonwasson (about $3) , then transfer to local shuttle bus (about $1.00) ride to the international boarder stop, walk across into the US at Blaine,WA From there take a WTA #70x express bus to Bellingham station(.75 cents), then take a WTA #80x express bus to Mt. Vernon/Skagit Station(.75 cents), then take a Skagit Transit #90x express bus to Everett Station ($2.00) and finally take a Sound Transit #510 express bus to Downtown Seattle ($2.50) This does work and is cheap & reliable just takes about 6 hours to complete. If you are wanting a quicker option and are willing to pay a bit more for it, check out CanTrail bus and Quick Shuttle both of which offer daily bus service between Vancouver,BC & Seattle but at a cost of about $40 one way. Good Luck

You can get a greyhound bus for about $30 per person. That said, you can usually rent a vehicle for a day for less than $50. It might be a better value to rent a car, because it's not much more expensive (with gas) and you can make your own stops for bathroom breaks, meals, etc.

We rented a car, but I am not sure if you can do one way rentals starting in Canada and ending up in the U.S. The other option is to contact the cruise line they offer the transfers generally as well.

I would go as a foot passenger on the ferry to Victoria, from there take the ferry to Port Angeles (very close to seattle) short bus ride and you are there.

hitch-hike