Where can I sell a used transformer?

I’m looking to sell a transformer I bought a few years ago to convert circuits.

The unit was quite expensive (around 800 USD) and is still in good condition. I heard you can sell used items at stores like HardOff but the return is quite low. Are there stores (for example, in Akihabara) that buy used electronics for a decent price?

I’m thinking of just listing it on Craigslist if I can’t find any places. I’m not sure if any people buy transformers on there though.