Soft drink or hot sauce store in Houston?
It's so much better if you can try a bottle before you buy in quantity, and sales tax is cheaper than paying shipping. Besides, they usually have stuff you can't buy at HEB, Kroger, etc.
I know about Soda Pop Stop, and I've even been there in person, but it's a bit of a drive...
Dave's Pepper Palace in Old Town Spring has a great variety of hot sauces. You can taste test most of their products to see if it's to your liking. The owners are very friendly and willing to order sauces that they do not carry. Definitely worth the trip.
Dave's Pepper Palace
26506 Keith St Ste A, Spring, TX 77373