Question on price / value of Sonus Faber and REL

My father has recently downsized and has some pretty good speakers, at least from my research.  I really have no idea what they are worth, and in addition, not sure they best way to sell them (Craigslist is a nightmare, especially for niche products).

I am no audiophile either, so that doesn’t help.  Hoping to get an idea of value and any advice on the best way to sell them - I’m in Nashville.

Info from the back of the speakers is below...

Two Sonus Faber Concertino, 8 ohm, black leather
Sonus Faber Solo center speaker, 8 ohm, black leather 
REL Strata iii subwoofer, black 

Thanks

Tom