Get up to 2000 free LingQs for inviting your friends. For every friend you refer who signs up, you both get 100 LingQs (up to a limit of 2000. If you need more, you can upgrade). And, for every friend who upgrades, you get 200 points per month! You can redeem your points for cash (USD) via PayPal once you have a minimum of 10,000 points ($100).