I have almost that exact spec Late 2012, with the difference of I have more RAM, and got the 1TB Fusion Drive.
I am sorry, but I don't have a straight answer for you, and I doubt anyone will give you one either, at least not an
accurate one.
Newer Macs are easier to gauge when it comes to how to price them, but your iMac is 8 years old now, and it gets a lot harder to accurately price older Macs.
While your iMac is (relatively) old, it is very powerful. The 2012 iMac with the i7 has a Geekbench score about on par with the 2017 iMac with the i5. The GPU is metal compatible, and was pretty powerful for an iMac when it came out.
But, buyers sometimes just see that is it 8 years old, and doesn't take in account what it is capable of. This could be due to official OS support from Apple (or lack of).
While I am sure your iMac's specs it would be powerful enough to run Big Sur, at least compared to other Big Sur supported Macs, the Late 2012 iMac is not supported at least not officially. Being stuck on Catalina, it will most likely be losing security updates in a little more than 2 years.
Thanks in advance for any help.
You have to have a starting place to determine price, I like to use eBay.
If you do a search for your Late 2012 iMacs on eBay, filter by auctions and time ending soonest and try to find a listing that is about to end, you can get an idea of how much people would pay for them.
An issue you will have determining a sell price with your Late 2012 is that your specs are rare (680MX GPU), so you will most likely not find an exact match. I just looked, and there are none, so you might have wait or use the i5 bids.
Once you find your price, then you have to consider how you are planning on selling your Mac.
With eBay, the risk shifts slightly to the seller, and there are also fees involved. But, eBay will most likely get you the highest sale/bid price.
I am unsure about your location, but you could try a local forum like Craigslist. This is typically cash sales that are face to face. No fees that either party needs to worry about. Generally, the risk shifts to the buyer, and the price would most likely reflect that, so expect a sell price for less than what you could get on eBay. While the risk does shift to the buyer for Craigslist, there are other factors that can make selling on Craigslist and local forums like it less desirable than something like eBay. Flaking buyers is probably the worse.
With selling on a forum's marketplace like MR, there are no seller fees, you can make the rules like payment options and if you will accept returns, and you pick who you sell to. Depending not the payment option, most or all of the risk shifts to the buyer. The biggest downside to using MR to sell is that you most likely will not get as much as other options like eBay.
There are some other options to sell, but the above are the ones that I am mostly familiar with.
Another thing to keep in mind that is isn't just about where you sell the iMac, but also about how fast you would like to sell it.
For example, if you find that on eBay, your spec iMac is getting bids for $700 shipped and you want to sell it on the MR Marketplace or Craigslist, you most likely will not get anything near that price or it may take a really long time to find a buyer.
You may have to drop the price a lot, or wait a while, or both.
Sorry if this is the wrong place for this please direct me in the right place if so.
The Marketplace forum would be a more appropriate place for this, but there are restrictions for new members so I am pretty sure that you do not have access to it.
I cannot remember the requirement for the Marketplace, but IIRC, I think it is 6-months time and 250 posts.
