I dont think bondo is needed, just resin, fiberglass, and sand it down heavily, then paint over it.
You can use bondo, but it will be more than 25 dollars.
25 dollars meaning
12-14 dollars for resin
6-7 for fiberglass cloth
5-6 dollars on paint, depending on how you paint it, you could use cheap black spray paint, then some cheap silver paint and brush on scratches.
The cost doesnt include a visor...so that will add 30-40 dollars if you want a visor.