I do not 'sell' any of my firearms. I had to do that when I moved from what was 'free California' back in the later 80's to what was then Communist Mass. (and still is when it comes to firearms). I had to sell ALL of my firearms to go help my Mom fight cancer. Including my Uzi.
Then, I left my country. In Finland I did not buy any firearms. Very complicated to do so. Moved back after 23 years and moved to Idaho. I will never sell one of my firearms again. I did make one trade though - I traded my SKS carbine with composite stock that I bought at a gun auction for $250 (I bought my 30/30 at the same time then had to come back home and tell my wife "well - oops I know I only had permission to buy ONE but... the SKS came up first so I bought it - I didn't think I would get that 30/30 which was what I wanted and when it came up I made only one bid and I got it too... I'll sell the SKS") - I traded it straight across for my 1911 that fires perfectly - as an old Indian would say "Hmm Good Trade"
Then, I was able to explain to my wife (who is Finnish) that "well, yes, you were right - I didn't need two rifles but, we do need a pistol - so we have to keep this one"
Now, we have two more pistols - and I am applying for my C&R FFL - my wife is deciding what kind of pistol she wants for herself
... I did pretty well I think!