Here is a website with an overview of all the second-hand stores in Amsterdam.
The IJhallen is a flea market where you can basically get anything. It is held twice a month during the weekend. More details can be found on their website.
Another way to get second-hand stuff is Marktplaats. It is a platform to buy and sell second-hand stuff. It is very handy if you want to buy budget-friendly homeware, bikes, clothes, or anything else that you can think of. Additionally, you can also sell your stuff if you would like to make some extra money! It is important to always pay attention to not get scammed.
IKEA has everything! Loads of students buy their homeware at IKEA. You can also look at second-hand or thrift stores. Other practical stores to get homeware are the Action, the Xenos, the Hemma, and the Blokker. Action is probably the cheapest store, Xenos has all sorts of tableware,