Gem Offers

Jungroup

Various videos (most times) 3-4 gems each

Persona.ly

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AdGateMedia

Sample Junkie – 240 gems
Nielsen – 600, 680, or 720 gems depending on which you chose.
Various surveys (after filling out info to enable them)
Final Fantasy – 1920 gems (for Apple) or 1600 gems (for Android)

Revenue Universe

VIP Voice – 125 gems
Smoothie Picture – 40 gems
ALL Dailybreak – 20 gems each