How long will this CGD last?

Just wondering how long a 4oz bag of Repashy superfood CGD would roughly last (the one where you mix one part CGD with 2 parts water) . Also where would you say the best supplier in the uk is? I was looking at lilly exotics as they deliver (a must for me) but if you think there is somewhere better let me know!

StumbleUpon It!