Sell or save

You can try Craigslist or USAudiomart for a free listing and the option for cash and carry, avoiding any fees. For something inexpensive, it really doesn't make sense to incur fees if you can avoid it. 

The only caveat is those two sites don't get the traffic that A'gon does. My Burson integrated sat for half a year before it sold and my Tonian Labs Tl-D1s are still listed now for over a year. They get tons of looks but I won't ship for fear of damage so that's half the story.

All the best,
Nonoise

Keep it as a spare if you think it will be useful someday in that role for you and you have no better spare already.

I like to listen regularly.  Having a spare keep the music playing when something breaks until it can be replaced.  

Spares are also useful for testing when something is not working properly.   If you suspect an amp problem for example, substitute the spare and see if the problem goes away or not.    Without spare gear to regression test with , correctly isolating a problem when it occurs to a specific component may be near impossible.

I came upon this question when it was the time to decide on QuickSilver M60. This time I found an unbelievably clean and desirable collection of vinyl records and sold my Quickies. They're now hard to find, but the records I have even harder to find. Overall I was happy for exchange.

I would say if you have the space in your house keep the Jolida 502 integrated you have. How old is it? The Jolida 502P I have from a couple of years ago is the amp section of the Jolida 502CRC Integrated and it can handle Tung Sol 150 tubes. With those tubes in your Jolida you can handle lots of speakers out there.

Regarding the sale value you will take it on the chin if you try to sell it. I've seen some Jolida 502 series amps used go for under $700 which is a steal IMO. You can try various sites like Craigslist but I just have mixed results selling audio gear on there. Lots of flakes, spam and the usual lowballers.

I keep spare amps to just mix things up and should an amp go which has happened I'll always have something to keep my speakers singing.

If you are not in need of the $$$, I would keep it unless you get a chance for a local sale.  As you say, to package and ship would be costly and always has risk.

I was just going through the same process. Through the never ending upgrade process, I ended up with an extra Parasound Halo Integrated, Mark Levinson 23.5 and Spectral DMC-20. I am on the fence about selling any of them, but I hate having them sit around not fulfilling their destiny of spreading musical sunshine.

I will most likely end up selling the Parasound and Spectral since they are redundant, and keep the ML 23.5 because it is such a sweet amp and it’ll be harder to replace in the future.

Keep it if you can or list it on Audio Asylum. I don't think they charge a fee and get good traffic.