Meineke wants $300 to replace vacuum hose? Is this too much?

Hard to know what they are charging you for, if the vacuum hose is in a place that is hard to access, then it could cost this much, but I would get another opinion. Have them show you exactly where the problem is, then take it somewhere else and see what they say. Here are some other shops in your area: http://repairpal.com/vancouver-auto-repair

The price does seem to be steep to replace one vacuum hose.