“up to”

some carriers do have deals like that but usually you have to commit to a higher tier service plan for X years where they make up the cost. it’s just a new form of carrier-subsidized phones from the 00s and early 10s.

for example, this is from verizon last year:

https://www.verizon.com/about/news/apple-iphone-16-pro-verizon-deals

Guaranteed trade in: New and existing Verizon customers can trade in any phone, in any condition and get iPhone 16 Pro on us, or up to $1,000 off the new iPhone 16 lineup with Unlimited Ultimate. If you choose our Unlimited Plus or Unlimited Welcome plans, you can get $830 off or up to $415 off the new iPhone 16 lineup with trade-in, respectively ^3^.

3 $999.99 purchase w/new or upgrade smartphone line on Unlimited Ultimate plan (min. $90/mo w/Auto Pay (+taxes/fees) for 36 mos) req’d. Less $1,000 trade-in/promo credit applied over 36 mos.; promo credit ends if eligibility req’s are no longer met; 0% APR.

so they give you a bigger discount if you go with the more expensive plans, and you have to commit to 3 years. if you want to opt out you have to pay back what you saved.