There are many dates in April and May at $183 for Los Angeles LAX to Vancouver, Canada YVR round trip tickets with American or Delta Airlines. American Airlines tickets are actually codeshare flights flying Alaska Airlines nonstop. United Airlines is about $10 more each way.
Even for peak summer travel June to August, there are round trip tickets available for under $250 round trip. These fares will likely go much higher, in the upper $300s to $400s, when trying to book this route two months from now in May 2016. Alaska cruise ship season tends to drive up airfare prices to Seattle and Vancouver in summer.
American Airlines codeshare ticket Alaska Airlines operated-flights
Los Angeles LAX – Vancouver, British Columbia YVR
$182.91 round trip Wednesday May 4 – Sunday May 8
American Airlines Los Angeles LAX – Vancouver, British Columbia YVR
$248.51 round trip Saturday July 9 – Sunday July 17
LAX-PHX-YVR-PHX-LAX = 3,200 flight miles (3,460 EQM for AAdvantage elites with 500-mile segment minimum for LAX-PHX flights).