OP, you answered your own question
"looking to raise some funds to offset upgrades".
check similar item's used value against current items for sale on hifishark.com. it finds items from many sites and links them all there. also shows past sales for more info.
have you sold before?. I sell my personal stuff only: LP's, Reel to Reel Tapes, Audio Equipment on eBay. I may list a few things here also soon.
it takes time: photo, listing, communicating, get packaging materials, pack, ship. and, you lose some of the money to selling sites (here, eBay, ..), money handlers (PayPal seller's fees ...). you get the money, but sometimes I think it isn't worth it, even though I'm retired.
I raised my starting price for selling LP's, I felt I was working for 'them' rather than me.
sell here: see other people's ads, get a sense of concise wording.
eBay is easy, once you get it down: be careful on the first item, think template, to be modified for each item. start with small inexpensive item. you want to keep a 100% rating, know that before you start.
original boxes, you may still want to double box, so you need a source for packing material and you need to know how to estimate shipping costs, including insurance. note: sometimes, unless double boxed, they will take your money for insurance then deny the claim later..
I made a new eBay account, and an new related PayPal account, so all/only buying/selling music related stuff is separate, and all the transactions show on one bank or credit card statement.
good luck,
Elliott