Google is inviting users who are over 18 years of age to participate in different types of online surveys and usability studies. You can get paid upto 75$ per hour depending on the length of a study.

The different types of studies are:

Usability study at a Google office: Typically, you will use a Google product or prototype, and give feedback on it. You could either meet 1-on-1 with a Google researcher, or work as part of a group. International users are welcome.

Remote usability study: A Google researcher will call you while you sit at your computer, and ask you to try out a Google product or prototype via your internet connection, and give feedback on it. You can be anywhere in the world, but need to have a high-speed internet connection.

Field study: Google researchers will come to visit you, and interview you about how you use computers or the Web. We won’t just show up at your door - we will always check with you, and make an appointment.

Online survey: you answer questions on the web or in an email, from your own computer.

Read all the FAQs here
Sign up herefor participating in Google User Experience Research

Via Labnol