My suggestion is you are unsure what to ask for it is Ebay.
You may think that HT600 is only worth $20, or you may think it's worth $200. I don't know about you, but as for me, I honestly don't know what a fair price is for half the crap I've accumulated thru the years.
If you're not quite sure what it's really worth, get on Ebay.
If on the other hand, you know what you want for the equipment, do it on Facebook.
The advantage of Facebook is no one is anonymous. You see a real name. You can google the name, and make sure it's a real name.
And make sure it's an actual ham. If you're selling ham gear, just sell to hams. Hams you can match the name on Facebook, with the call on the ULS.
And you can match the address you are shipping to, with the address on ULS.
Two things that will greatly reduce the probability of you getting ripped off buying and selling.