I was in the same boat as you. I went to my LHBS and the price to get an inline shutoff valve was over $30. (valves, barb, coupler, etc.) I needed 2 so this would bring the price up to over $60. I found tap locks online for around the same price. I could probably find the valves online cheaper, but in the end I decided as the above poster mentioned...disconnect the QD's from each corny. I had a lock on my fridge and while it wasn't optimal, I didn't feel like spending the money for this. I felt that no matter what I did, tap lock, shut off valve, or disconnect lines, it would all take about the same time to do when I wanted to serve up a pint. An inconvenience no matter how you look at it. But maybe a necessary one.