S.C.
It's not definite money (you have to qualify), but it could bring in some extra cash:
Schlesinger Associates is a local research company that runs focus groups on everything from dining out to cosmetic surgery. Most are consumer-related focus groups. They usually last 1-4 hours and pay $50-250 depending on the topic and amount of time the focus group lasts. Their office is on the Dallas Tollway not far from the Galleria.
Go here to register:
https://db1.schlesingerassociates.com/sch2/PreRInternet.j...
Once you sign up, you will receive email when they're recruiting for a focus group, and sometimes they'll call.
While I haven't been able to participate in a group yet (I work full time and the evening sessions fill up), I know people who have and were impressed with how it went.
Good luck!
S.