These yellow kiosks, which you can look for one near you here, allows you to exchange your gift card for cash. That doesn't mean you'll get what you consider a fair amount. Don't expect to get full (or even close to full) value of your card. From what I've read and seen in videos online, it will vary by location. Your gift card may need to have a minimum balance on it to use the service. I have seen $20 and $25 respectively, so definitely double check. You have the option to accept the offer or refuse it.
Don't forget: You can dump your old change in the green Coinstar kiosks and get full value of your change as a gift card. YMMV on which cards are available at your kiosk, but if you have a jug of change, it's always an option as many banks don't want to take rolled coin anymore. Their rate for counting it and giving you cash back is nearly 11% of the amount, so a gift card is definitely a better option if you have a specific retailer to use it at in mind.