IMHO, try finding one with a keyboard.
Logitech's CREATE keyboard is a great case if you want something that works with the Smart Connector and offers more than Apple's Smart Keyboard, but at $150, it's not cheap as well.
I'm thinking of getting an IVSO keyboard case from Amazon at $35. It doesn't work with the Smart Connector as it does so over Bluetooth, but it should work just as well. Plus, as an added bonus, it works with other devices too.