Change my iPhone for another one

Hi! I live Brazil but I've bought my iPhone 8 plus at USA. In January, I'll come back to USA and wanted to buy a new model. I heard that if I gave to Apple my iPhone, they would give me some money to buy a new one. My cellphone is in perfect conditions, and it never was 'opened' in another store. I would like to know if this information is correct, and if you have any idea of how much Apple would give me for my iPhone.

If it is true, is there any possibility of you pass my data to the new iPhone, when I buy it? Like my photos, my contacts, my apps... Almost passing everything I had in the old one, to the new one.

*My iPhone has 64 GB

*Sorry if there are gramatical mistakes

Thanks for the attention.