AT&T today announced that it is offering T-Mobile users up to $450 per line to switch mobile networks. And while the deal may look good on paper, there are some serious flaws that make it not such a great deal for new AT&T customers.

To break the deal down, T-Mobile customers can get two credits applied to their account: one for $250, and one for $200. The first $250 credit is applied to a new AT&T switcher’s bill when they trade in their old, yet still relatively new, T-Mobile device in good condition. This isn’t such a good deal since a semi-recent smartphone in good condition will likely fetch more than $250 if sold directly without a middleman using Craigslist or eBay.

The second $200 credit is only applied to a new customer’s AT&T account if he or she has activated an off-contract AT&T device or brings their own unlocked handset. So if you’re looking to purchase a subsidized phone on AT&T, you cannot take advantage of this offer. Also, this credit is only applied to your AT&T bill after you’ve paid your bill for 90-days.

Honestly, the more I look at this deal, the more I think it’s a total ripoff. You can easily get $250 or more in cash for your old T-Mobile iPhone or recent Android device on Craigslist, and if you’re one for subsidized phones, you’d likely lose out on more than $200 by purchasing an unlocked device to bring to AT&T.