I'm no expert Ed, I just happen to have one!
but ... oh ho, what's sharp mean
I honestly don't know. "the internet" says the 500G's Rikenon is either very sharp or mediocre.
The way I shoot doesn't really lend itself to worrying about lens sharpness too much as I'm often underexposing wide open at barely hand-holdable shutter speeds without support of any kind.
here's a sample anyway, on Fomapan 100 and stand-developed in Rodinal:
To me, a good price for a camera is really the amount either I'd be happy to receive if selling or the amount I'd be happy to pay if buying.
So in my case for one of these, about £30 I suppose. But this little camera was sold under many different brand guises, so as well as Ricoh I believe there are Agfa and Konica and maybe Vivitar versions, and some are "rarer" than others and I've seen them on eBay for silly prices.
Inserting a small square of blue lighting gel over the LH part of the viewfinder helps the contrast of the rf patch, by the way, and makes focusing a bit easier.
hope this is in some way helpful ... I'd agree, just use it with S16 and I'm sure you'll be able to get decent shots and enjoy it.