How much space do i need for a full movie bought from the Playstation Store for my PSP?

May be...

what size of memory should i get

i Don't know about from the playstation store, but the movies i get from friends for psp are about 600-800 mb per movie. They have gotten as low as 200 mb for a 2 hour film(dead man on campus). I'd get a 4gb memory stick since they are the best price for memory. they are about 80$. 2gb are 40-60$. and 1 gb are like 20$. i wouldnt go any smaller than 1gb. if all your gonna do is watch movies then i would reccomend 2gb. if you want music and flash games for internet browser too, then i would get 4gb. Right after you buy the memory stick, go to the far left menu, and format it. doing that will put all the folders you want for psp. then just go to psp folder and place movies, music, in the corresponding folders.

Buy a 4 GB memory stick. Just to make sure it certainly fits. Remember, delete from your memory stick when your done.

4gb are getting cheaper everyday, but if your on a tight budget, choose 2gb, if not 8gb is the best option