Have you had an awning previously on a RV? For a higher price, you get more features, like power operation and automatic operation. The least expensive power awning could be a step up in price and down in quality. Check the online catalogs of mainstream awning manufacturers Carefree and Dometic/A&E.
For a manual awning, I would not recommend anything lower than the Dometic 8500; I've seen cheaper manual awnings, but they are not as well braced. The 9000 series is similar in structure but with acrylic fabric and weather shields, for almost twice the price, overlapping prices of lowest cost vinyl fabric power awnings.
Carefree makes a vinyl fabric manual awning for about half the price of the Dometic 8500. I've helped people try to recover from wind damage on these, and that experience would keep me from recommending or buying their cheapest, unless you operate in low wind areas. However, Carefree offers a wide range of hand cranked and power awnings, some of them unbraced, that are easier to operate than the manual Dometic.