iMac

if it has trade-in value, apple will credit that value to your new purchase. and if it has zero trade-in value, apple will recycle it for you for free.

either way, I would recommend the steps in What to do before you sell, give away, or trade in your Mac before bringing it in.

You can go to this Apple site and see what the trade in value for you iMac is: Turn the device you have into the one you want.

you're getting another iMac or computer you'll have to get an Apple gift card to apply to the purchase of any other devie.

Please review both Apple Trade In and also Apple Recycling Programs to see if your current iMac has any value.