I found a few Asian Home Gourmet seasoning packets in the import section of Carrefour supermarket. There’s a lot of different Thai, Indonesian, and Singaporean seasonings and some of them are gluten/wheat-free!
The Thai Green Curry looks like it’s gluten/wheat-free. At Carrefour, each packet costs about 12 RMB. In the U.S., you can get them from Amazon.com or direct from Asian Home Gourmet for a little less than $2 USD.
Ingredients: chili pepper, soyabean oil (partially hydrogenated oil), garlic, salt, lemongrass, shallots, natural shrimp, galangal, basil leaves, white pepper, coriander seed, fish sauce (anchovy extract, salt, sugar), cumin