Pokemon Shuffle released last month on 3DS as one of Nintendo's first (but not the first) forays into free to play gaming. It was... not entirely successful. Reviews are all over the shop (we haven't run one since you can download it for free), most of which criticise the game's microtransactions and 'pay to avoid waiting ridiculous amounts of time' monetisation strategy.
Now, however, it appears that the same 3DS browser exploit that allows Game Boy Colour ROMS to be loaded and played also allows people to bypass payment completely. Nintendo Life reports that a very similar method results in all the shop prices being set to zero, though it requires firmware v.9.0-9.5, which means that New 3DS owners are out of luck.
Naturally we'd suggest that you don't try it, or go out of your way to look for instructions, both for legal and ethical reasons. But either way, it's interesting, no?