There are at least three types of attached awnings commonly used on small fiberglass trailers. Jim, you have a case awning, which is what Scamp
and others install as options from the factory. The awing and supports roll out from a solid aluminum case. As you have discovered, they are pricey to replace.
Bag awnings and rope-and-pole awnings both attach to the shell using an awning rail, which is a C-channel with an attachment flange. Typically they are riveted to a fiberglass shell, but I've also heard of people using VHB tape. A bag awning self-stores in a bag that hangs on the outside of the trailer. A rope-and-pole awning is removed and stored when traveling. Cost is maybe $2-300?
For a variety of reasons, cost being one, we use a freestanding awning. If you go that route, I'd strongly recommend paying a bit more for a straight-leg, rather than a slant-leg, design. You get more shade, it can be set up close to the trailer, and you can get side panels.
Another freestanding option is a Clam shelter. A number of forum members report liking it a lot due to lighter weight
and easier 1-person set-up.