If you'd like to read about the types of oats out there, check out the self-reliant sisters link here. Lisa (the gal who runs that blog) is a really amazing gal and keeps up on so much information for it, it's a wonderful resource. Personally, we store almost exclusively quick oats. My kids prefer them and they never notice them in the bread recipes I've tried (which is a big bonus!).
They suggest that you get at least 25 lbs. per adult of oats. They need to be stored in a long term storage container (such as the #10 cans, 5 gallon food-grade buckets, or pouches) and have a shelf life of up to 30 years. we try to use buckets as often as possible, they cost about the same as the #10 cans, but we can re-use them. So it's a one time investment, versus every #10 can we use costing us an additional $1.
We just bucketed 100 lbs. of oatmeal this week, and I was surprised at how much we were really able to store in each bucket. We pushed the food down a bit, to make it hold more & we were able to store 19.5 lbs. per 5 gallon bucket.