SD Card Capacity
A single RAW plus JPEG image requires 40MB of space.Full HD video (1080p) requires 363MB per minute.
Therefore, a 32GB SD card could hold:
800 RAW plus JPEG images.
or
88 minutes of full HD video.
or
400 RAW plus JPEG images and 44 minutes of full HD video.
My 32GB card is marked "2 Hours", but this is calculated on shooting 720p video.
If you only shoot JPEG then the file sizes are much smaller, around 6MB, and you could expect to fit 5,000 images on a 32GB card.
Card type
To record video you need a class six or above SD card. I use a class 10 and there is no real price diffeential these days anyway. The only issue can be counterfeit cards of lower classes being passed off as class 10 so best to buy from a reputable source.I recently bought a Sandisk Ultra SDHC Memory Card - 32GB - Class 10 - UHS-I for £13.50 from 7Dayshop.com. As a teenager I was paying £6 for a 200 second cassette of Kodachrome Super 8 that could only be used once, so the cost of these cards is not a big deal.