Can i switch my sd with a iphone and get the same plan?

I have a samsung and i would like a iphone 4 i would like to buy an iphone model and put my sd card in so i don't have to spend more money with a plan

Yes you can do this, but the iphone has to be from your carrier (i.e, if you have a at&t plan you have to get an at&t iphone), or you can get an unlocked iphone which can be used with ANY carrier, however these are expensive

SD cards are for pics. I'm assuming you mean SIM card but yes you can. You'll need to get the iPhone unlocked.