Well... it's not a hex, but I absolutely love the 5.5 gallon I got from Petsmart. It's their brand, Top Fin, and I recommend replacing the filter with a better one (I got an Aqueon QuietFlow 10 for it), but the tank is sturdy and I actually like the hood that came with it. Plus, it was only $30 for the whole kit. :)
BUT If you have the room for it... there is also a 10 gallon kit for $30. It'll give you more room (for potentially another betta hee hee) and the cost will be basically the same because you'll want to replace the filter that comes with it. Of course, that's just me being picky about filters... I haven't tried it, so for all I know, the filter is just fine.
ETA: If your heart is set on a hex, there is a 5 gallon hex. But it's $50, so not quite as affordable as the others. Very attractive tank, though!
Sorry I'm only listing Petsmart stuff. That's really all we have around here, so that's all I have experience with.