I believe they can do this since they are exempt with their resevation status. Most of the Indian sites are legit and safe to deal with. They can sell for less but I believe most states now require them to add your state’s (Texas?) sales tax in with your purchase. You can also add about $20 for shipping too. They only ship UPS and require an adult signature.
You may want to look at Lil Brown as well to compare prices: www.lilbrown.com
It’s also an Indian reservation site, and they do tack on state sales taxes, but the half dozen times I’ve ordered cigars from them over the last 5 years they’ve been very helpful, and their prices are less from what I’ve found elswhere.
Thanks