$8 for me at PepBoys, but I bought extras in case I screwed it up. 15 minutes under the hood, since I literally have never done work on a car before (not even an oil change).
Was quick and easy - very detailed description. Had a hard time getting hose #1 in the diagram above off of its male counterpart, but a good bit of force eventually removed it.
Most noticeable to me was how much more quickly boost was gained once the turbo was engaged...1 PSI...3PSI...18 PSI. Also, I feel as though I noticed that the BOV and turbo itself were both making more noise during acceleration - but maybe that's just because I was paying extra careful attention.
Strongly recommend this to anyone that owns a pair of pliers and a pair of scissors.
Thanks OP!!