I used the following apps on my android for the first 9 months of the year and made around 2k.
90% of my earning came from Gigwalk and Easy Shift.
Field Agent: (2 hour reserve time) doing surveys may get you a free product to review.
Gigwalk : once you finally get approved for a shop you can self assign. Easy shops
isecretshop: is a intelli-shop app with more listings.
Easy Shift: (24 hour reserve time) Easy jobs but, competitive in my area
Zappidy (first come) only found a few $4 jobs on Sundays checking Target Demo's
Mobee I have done a few but, you never know the task until you start and several are too much work for little rewards (gift card redemption)
Presto Mobile: choose a area and it maps all shops. Great for finding new MSC's.
Mob Job: 2 months and not a single listing yet
Gigwalk and Easy shift have Facebook pages and the group post when new shops are listed.