I've never got around to adding QDs into my kegging setup. I'd like to, but it just hasn't been a high enough priority for me to purchase. Anyone have recommendations for the best place to purchase from? MoreBeer has these: https://morebeer.com/view_product/17398//Beer_Gas_Tubing_Quick_Disconnect_-_In-line_W__Shut-off_Set but they seem expensive. Is that just what I should expect to pay?

Take a look on this page and others at this site. They have better prices and surely better customer service than More Beer.

http://www.usplastic.com/catalog/item.aspx?itemid=23885&catid=743

kinda hard to tell by the pics but which ones stop the flow of liquid/gas when disconnected? lookin at some for my co2 tank.

Those will say "shutoff" and you definitely want that style.

BB, thanks for the great info. The ones that say "coupling," does that imply Male-Female set?

I don't think sets are sold. You have to buy the appropriate male and female pieces. It is confusing.

BB, thanks again. I'll give US Plastics a call this week to clarify and probably order some.