I think you won't find a new pulldown awning at that price, but there are often some for sale used.
Here's one for sale right now for $365.00 Used rv awning - Yakaz For sale
and it comes with all hardware. (That's assuming you have an awning rail on your rig already...)
Measure the length on your unit to get an idea of what it will accommodate, and start watching Craigslist etc. You also might try dealers that do awning replacement- sometimes they have perfectly good awnings taken off rigs that "upfitted" to electrics, etc.
If you're lucky, a used awning might come with mounting hardware like the one above but if not, it's often readily available from awning makers. You probably should make sure of that before buying a used awning that doesn't come with mounting brackets.