I just saw Gizmodo’s post on HP having released iPhone/iPod Touch app emulators of their notable calculators.

HP 12C:
This is arguably the most famous HP financial calculator and has sold well for decades. The app that emulates this is $14.99 and 1 MB.

HP 15C:
This is the HP 15C scientific calculator. This app comes in at $29.99 and 1.6MB.

Read Gizmodo’s post about this for more information about these.

[My opinion]
As Gizmodo made clear; the physical calculators that these emulate are significantly more expensive (many times more expensive) and are perfectly emulated by this app. However they don’t mention that most non-free apps in the app store sell for about $1.99 (most sold are probably free!) and that makes the price tags of $15 and $30 irrelevant in most sense of the matter. However, if TI wants to make a graphing calculator app to save high school students (most of which have iPod Touches or iPhones) from having to buy the hardware analogues.
[/MY OPINION]

Links to the app:

• HP 12C
• HP 15C

This post significantly draws from Gizmodo’s post about these calculators.