for my iPhone5 in an Incipio StashBack case. I always keep my iPhone in the StashBack case because it also doubles as a wallet, keeps my credit cards.
i bought the Sport Armband form Tune Belt AB87 on ebay it was about $20.00 and price was the main factor. The Armpocket bands cost twice as much.
review (bad):
-the iPhone5 inside the Incipio StashBack case fit inside the Tune Belt AB87 but it is a tight fit.
-the arm band strap does not go all the way around my arm easy. I am an average male (6' 170 lbs) and still the arm bad did not fit. Kinda bad, i can think a few extra inches of material would not cost that much.
if I update my iPhone next year i might buy an even largerr ArmPocket unit that could accommodate the iPhone + ncipio StashBack case + mobile charger. Still tho dont know if the ArmPocket strap will be long enough.