There are 6 items available for purchase using real life currency in the SFH:E Shop. They are:
Uses: 3 x Invincibility Powers
Price: $0.99 for 3 uses
Description: Enable this power in game to become invincible for the rest of the stage! (Campaign Mode only)
Double Coin Hack
Uses: All Money Earned is Doubled
Description: Hack the game to receive double the coins from playing!
Mini Coin Pack
Uses: 1,000 Coins
Description: Need a slight boost? Look no further!
Small Coin Pack
Uses: 3,000 Coins + 500 Free!
Description: Need a slight-but-little-bit-more boost? Look no furtherer! [sic]
Medium Coin Pack
Uses: 5,000 Coins + 1,500 Free!
Description: Just the right amount... Or is it?
Large Coin Pack
Uses: 10,000 Coins + 7,000 Free!
Description: Gotta catch em all, and you just might!