Best way to sell used games?

Easy. Build another bookshelf.

Or, you could try trading at a local meet-up. You won't get what you put into it initially, but there are sometimes some decent trades. It really depends on what other skills your wife has, which will determine her trade in value.

I've had success selling/trading them over FB marketplace and Offerup.

Don't expect to get what you've put into the games. Used is used no matter what and people rightly expect a good discount because of it.

I found that selling the game on "public" spaces like ebay or local variants will often be sold at a heavy loss. Unless you are selling something not so common, expect many offers for the same game, often 60% or more reduced. At the moment we still have the space and so decided to hold onto them for now. We have offloaded some of the less played games to our house in the village and only can play those whenever we are there.

I list them on Kijiji (a Canadian local marketplace website). You typically have to wait a while and relist, but they eventually sell.

Facebook Marketplace, to dedicated groups. I don't like using Facebook, but it's selling pretty quickly everytime.

Otherwise, there's a FLGS that does used games sales every season. You bring your games and if they sell, you get credits to use at the store.

I just do eBay tbh. Having the shipping all sorted for you makes it a breeze. Not the best bang for buck but I prefer the convenience over having to deal with constant haggling on other market places.

This is my go to approach to sell games:

1. Ask with your friends and gaming groups
2. Check with local stores, sometimes they have events that allow you to sell/trade your games.
3. If those two fail, try your luck on Facebook marketplace.

As a rule of thumb I usually discount 30% from their retail price. Depending on the status of the game it may be cheaper or more expensive.

Also be open to trades, sometimes you can get a game that you wanted to try or that's easier to sell.

If you want to sell them ASAP bundle everything together and offer them at a big discount.

I use board game geek marketplace. Then use pirate ship to quote and calculate shipping. I’ve sold a dozen games that way, as long as you list the game cheaper than others you’ll get messages about them.

Enter your games in to GAMEYE. If their value seems worth your time, then double check the current market value by checking recently sold listings on eBay or by using Price Charting.

If the value is still there, I would say eBay is your best bet unless you happen to know of a community of gamers where someone may be looking for the title (like, say, a retro gaming convention) If you try to take it to a retro game store, they'll (necessarily) low ball you since they need to make a profit.

@Beardsley Interesting Question. I would support the "extend the storage" solution.

I made no good expierience with local trades, but at our capital boardgames trade fair, in the used corner, I did some acceptable sells. Also Ebay gave me some deals....