. Mm nice tasty snack! Such a vision. It is fine for hamsters to eat insects and what they would do in the wild. Hopefully the hamster would be discerning enough not to eat a wasp however. And as MMMD said - you will need to avoid the use of things like fly spray (which could be toxic to a hamster) or any aerosol spray like air freshener as well.
Afraid I don’t know about Craigslist as in the uk. Is it like eBay? If it’s just second hand sales I would think it’s ok providing there are secure payment methods as I’ve heard of people using it.