What area do you live in, and what are the chain stores in your area? Petco sells some decent tanks by National Geographic and Aqueon, but they usually don't carry anything over 55G in the stores. Most can order larger tanks however. Petsmart usually carry Tetra brand tanks, which are serviceable if not fancy.
I've bought several perfectly good used tanks off Craigslist for reasonable prices. The advantage to buying used tanks is that you can often get heaters, filters, and lighting with the tank. Just be sure that you get to see the tank fully filled if you go that route to be sure there are no leaks. And, if they come with a stand, inspect the stand fully. A weak stand can be an instant nightmare if it collapses with a full tank on it.