CashCrate is a very good gpt. It has the best referral system I have seen. You earn a bonus 20% of your first level referrals and 10% bonus on their referrals. Every time your referral meets the minimum payout of 10 dollars, you earn 3 dollars. The more active referrals you have the bigger the percentage bonus is. There is 5 different levels.

Bronze Level - 20% first level - 10% second level
Silver Level - 25% first level - 10% second level
Gold Level - 25% first level - 15% second level
Platinum Level - 30% first level - 15% second level
Elite Level - 30% first level - 20% second level

CashCrate has a lot of offers ranging from .15 cents up to 20 dollars. After completing an offer you earn 1 point. The points can be used to buy gift cards, digital cameras, Ipods, Xbox 360's, and other goods. CashCrate has 3 daily surveys each worth .80 cents. They also have cash back shopping. I highly recommend Cashcrate because of their referral system and amount of offers. Click here to join.

General Information:
Minimum age to join: 13
Mimimum payout: $10
Payment processed: On the 20th if you meet minimum payout the month before.
Payment type: check
Internation members: Yes, but most offers are for the US. There are a lot of offers for Canada.