Edit: This company has a minimum order of 10 pieces per item. So for one simple connection you would need 20 items. Even at $1.20 a set you'd pay $12 plus shipping. If anyone wanted to go in on a group buy I'd do it.
I found another source of Quick Connects that has built in valving - when you disconnect the flow is stopped.
They have basic Twist-and-Lock Open Flow connectors as well.
One downside of all these connectors is that the hose barb has a "lock-on" style shoulder - once the hose goes on it is permanent. If you want to remove it, you have to cut it off.
Here is a Kent Systems,Collection 4 sampling:
Basic connectors are under $1. Valves are under $3. Be sure to specify the Hose ID - typically 1/4".