It only worth something if you have managed to sell it. I can say that mine worth 7500-8000€, but so far it just occupy a room and the time it takes to sell one item at a decent price is between 3 days and 2 years.
Yeah, almost everytime I sold an old game/DVD/Blu-ray on eBay or Amazon Marketplace for around €20 - €30, I asked myself if the time and effort spent for that was worth it.
Researching the 2nd hand worth, writing a small text, answering questions, checking incoming payments, wrapping up the game, addressing the mail, driving to the post office/mailbox all add up. Some of these are only optional, but you'll probably spend at least 30 minutes in total, in some cases over an hour.
I have given up with this and I am now investing in the stock market. I managed to obtain in 3 months, what I have earned with retro game reselling in 1,5 years.
Important to precise: yes you can make a lot of money with trading on the stock market, but it is a myth, the idea that you can make a lot by doing nothing. If you want to be efficient and not be in a risk of losing money, you need to be constantly watching the graphics and transactions. It is time consuming and it is an activity of parasite.
Here is my only one game currently in sale, I try to push the price by providing nice service and pictures. But this PAL Secret of Mana, even in negative margin I struggle to sell it.