The SD Card that will be in that bundle is in fact a 4GB one. You should have at least 26,432 free blocks at the start on the bundle, assuming you don't swap SD cards.
I have over 27,000 blocks left on my 8 gb SD card, and I have quite a lot of eShop/ambassador games, even a full retail game, 300 songs, and a bunch of pictures.
8 gb SD card is perfect if you don't plan on downloading too many retail games.
The SD Card that will be in that bundle is in fact a 4GB one. You should have at least 26,432 free blocks at the start on the bundle, assuming you don't swap SD cards.