I also travel to see James. It is a long drive so if there is something in particular I call and make sure he has it in stock. (ie red legged crabs)
Occasionally, when in a pinch I have found stuff @ Pet City on 1960. Their fish person however is the only one that knows much about saltwater fish. I have purchased some dry goods there.(selection is hit or miss)
Sponsors that have always treated me well....
Gulf Aquaria online... I think they are located in Tomball area but do not have a storefront and their delivery time is awesome.
3rd Coast got an awesome deal on salt nice fish and coral. As well as Sapphire Aquatics for Nano skimmers all on off 290 so if you take the tollway your a little closer.
But, mostly it takes a scheduled trip somewhere far....sorry