A lot would really depend on what you’re looking to do while you’re here. Assuming you’re here to check out the city itself, I’d say stay somewhere a little south of the river (the Colorado river which is Town Lake, or Lady Bird Lake as they call it now) and just stay west of I-35 and you should be fine. That way you’re not paying downtown prices but you’re close to the action with maybe a $10 cab ride to 6th street, near Zilker Park, South Congress etc. If you want a place with a little Austin flavor you can check out the Austin Motel or Hotel San Jose although both are going to be more expensive. If you don’t mind driving a bit to get around you can find places a lot cheaper a little further out. I’d stay somewhere near Mopac (local Loop 1) since it’s a lot easier to get around than relying on I-35. What are you doing while you’re here and maybe I could help a bit more?