Here are a few Tequila brands that you can search for in Mexico:
Reserva de los Gonzalez (son's of Don Juilo, excellent Tequila not found in US)
If you're lucky you'll find some Tres Magueyes in your search...
There are still quite a few 100% agave tequilas available under $40.00. Sol Azul, Fina Estampa, Hacienda de Oro, etc. Plus the Hacienda de Chihuahua sotol products are tough to beat, and very affordable.
Check http://www.tequila.net for more info, and to see top rated tequila brands and other agave products.