Do you have a whole foods store or co-op in your area? Any place that sells bulk food, esp. whole grains, should carry it. Some feed stores carry it too however it might be called linseed so check for that name. Flaxseed often denotes human grade consumption while linseed can mean livestock feed grade.
In case you're wondering linseed/flaxseed is where linseed oil comes from.

Have you tried ebay?

A local grocery store near my home has them in their bulk section. I beleive it is 35 cents a pound. I buy it to feed my chickens. It isn't more than 60 cents a pound for sure! Winco is the name of the store. Cub Foods in some areas.

If I use Flaxseed for a heating pad ,do I have to process it or treat it somehow? Will microwaving it do damage or cause odors?

i know i'm late commenting, but i just saw flaxseed(for consumption) at Sam's. i don't remember the price but i almost bought it for my diet after watching dr. oz. maybe i'll buy it next week. maybe petsmart has some in bulk you could use for heating pads.

kudzukween, thanks for posting! I still am unable to find flaxseed or linseed at a reasonable price in volume. Can you tell me what section of Sam's you saw it? I never would have thought of them!

Here is a link that might be useful: Where to buy flaxseed for crafts?

I used some one time that I bought at a country feed place,. One thing I found was that I didn't like the odor if it was overheated. I make a lot of hand warmers and I like to use dried hard wheat from the bulk food store. It is more expensive than rice but I like it better than either rice or flaxseed. I do like rice, though, better than flax seed.

These people may hjave this dried flower warehouse look on internet

Flaxseed is sold at Sam's Club near the vitamins and supplements.