Pretty much any functioning laptop will find a buyer if it is capable of running a modern web browser and in many cases there are enthusiasts willing to take hardware that can't even do that.
Over the past couple of years I have sold hundreds of bits of old computers ranging in age from five years old to 25 years old. Everything from ThinkPads to 20 year old power supplies taken from scrapped Compaq desktops and all the components in between including tape drives, DEC terminals, etc.
I also sold a non-functioning Quad 303 power amp for 1000 NOK (112 USD). Could perhaps have got more for it but as it hadn't cost me anything and it had been waiting for repair for over ten years it was a good price.
Someone will want your Mac mini, they just need to be able to find it. Put it on Ebay, Gumtree, Craigslist, Finn.no, or whatever your locality has.