[lVpU2VRe30XG]

Where is the best place to sell stuff?

Marketplace is full of scammers or poor people trying to get stuff for half of the price listed
Nobody uses craigslist
ebay gets you with fees, taxes, and shipping

I've got merch but cant move it.

[smithakp1]

It has been eBay for me, always - not happy about the fees and cancellations by buyers though

[Vortiger]

I've been using Shopify, but to be honest, it depends on what kind of merch you're planning to sell.

If you want to use a well known site, instead of advertising on your own, you could use Amazon or Etsy. Not sure where you're from but specific countries have a local online marketplace where you can sell items aswell.

[Elon Weiss]

Where is the best place to sell stuff? 

Marketplace is full of scammers or poor people trying to get stuff for half of the price listed
Nobody uses craigslist
ebay gets you with fees, taxes, and shipping

I've got merch but cant move it.

Ebay has by monthly seller fees reductions usually 80% off the usual 12% they take, so not so bad in the end.

Ebay does however 99.99% favour the buyer in disputes, which is kind of annoying.