Seattle, WA to Vancouver, BC buses and trains from $15

Or, see buses and trains from Vancouver, BC to Seattle, WA.
Here are some trips other travelers have found on Routefriend.
$15
4h 10m
0 stops
Greyhound
$30
3h 0m
0 stops
Amtrak
$150
13h 49m
2 stops
Amtrak Amtrak