The first Infinity Blade wasn't the deepest of games, but the touch controls and rebirth mechanic were compelling enough to make up for it. The next two games improved the formula, relegating the original to electronic aether for most people, but if for some reason you want to play all three together, you can currently grab the trilogy at a discount.
It's advertised as a "$5 deal", but due to Australian App Store pricing, it comes out to $6.49 in the polymers. Still, with the individual games selling for $4.99, you save yourself $8.48. Unless you already own one or more of the Infinity Blades, in which case the deal is less appetising.
If you've been wondering what the IB fuss is (or was) about, this is almost as good as it gets in terms of discounts. Developer Chair Entertainment might offer the first or second game free at some point in the future, but even then you're still saving over three bucks.