How can you sell things to cash converters?

First you need to make sure the store is interested in your "things".

Second you have to be within legal age, in most states a minimum of 16 & have 100 points of ID.

Third you need to have an idea of what you're looking to get, most stores will pay 1/4 of the current retail price which allows for store expenses, profit & discounts.

And last you need to remember they will offer you a price, not obligate you to sell your stuff, so you can always get a second opinion elsewhere.