He's certainly cheaper. But he's definitely not better. So, it's not a "better deal" except in the way that a new Chevy is a "better deal" than an older Ferrari that still has some life left in it. Talib is a pro-bowler and so far Fuller isn't. Maybe he'll be great in future, but right now he's not even close to the player Talib is.
The real reason the Chiefs didn't jump at that Denver offer is because the entire story was B.S. from the word go and the Broncos never offered it.