Do I remove my SIM card when I trade in my phone?

So I'm with consumer cellular (a cheap prepaid phone service) so in order to get on their plan with my iPhone I had to buy a different SIM card to put in my phone for the service. I don't like the service anymore so I'm thinking of trading in my phone to either Apple or sprint and upgrading. Would they take my phone with the prepaid services SIM card or would I need to remove it?

You need to remove it, your number is on there.

The SIM is yours since it contains you phone number & contacts (if you store them there).

Yes to much information is on it to leave it in there