Not much on anything, but that depends on what you are using.
8 MB
With a memory card you have a larger amount of memory on your phone. However much is on the memory card. So more space to hold pics and etc.
200
a psp can hold 64gb card or 34 gb card
1 gig
I'm not sure about how much memory they can hold so if i make a mistake please correct me Grey memory card 50 blocks : 5$ Black memory card 100 blocks: 10$ White memory card 1000 blocks: 20$
about 300 in a 2 gb micro sd card
The R4 doesn't hold memory, it's the MicroSD card that you insert into the R4DS that has storage. It will support MicroSD cards with storage of up to 2GB (non-SDHC).
2GB up to 8GB
depends on the size of you SD or SDHC card
it can hold about 5-10 hours depending on video resolution.