Watever it is, im just stating my own point of opinion.
If i ask my fren(a non marine aquarium hobbyist) with internet access to post the sale for me. I dun think he will be interested to know the market rate/price of watever marine stuff i'm selling.
whether or not it will aid sales, if you think it does then it does.
Anyway, if im the one selling the chiller, i'll ask my fren to post my number too so that potential buyer can contact me to discuss and neg.
Unless i make known to my fren how much i want to get back for the chiller and he can earn the commission if he manage to sell it at a higher price