Buying tickets - get 5th day free?

[NYEmomma]

We have always bought our tickets as part of a package when booking our resort, dining plan, etc etc etc. This is our first trip renting points and buying things basically ala carte. As I was searching for the best price on tickets, I see from various sites that they're offering the 5th day free on a 4 day base ticket. Is this a common offer? We'll be going again in a couple of years once SW opens in HS and if this is a good deal, I'm wondering whether it would make sense to buy those tickets for our next trip now??? Is there some obvious reason that this is a BAD idea that I'm not thinking about?? We'll be renting points again on our next trip too.

 

[Robo]

Very common.
While the offer is fine, it is not actually an outstanding savings.
The difference between a 4-day base and a 5-day base is $20.