Good place to purchase heirloom seeds

Ideally I would like to find a local group to swap seeds with, until then I would like to find a reputable source. I want to get some quality seeds, up until now I have just purchased what I can find locally (mostly Burpee or whatever is available at lowes). I have found Baker's creek which is really great, but one oz of Emmer wheat is $3. I'm trying to visualize an oz of grain and it does not seem like a lot.

I have a small yard. I'm fine shelling out some money for heirloom veggies as a few seeds and yield a lot of fruit, but for a decent grain that just seems unreal. What seed sources do you know of that are moderately priced and high quality?

The highest quality seeds that I can obtain are those that I have grown myself... They get perfectly tuned to the environment and to my way of doing things... The next highest quality of seeds that I can get were grown by my neighbors. Since I choose an introverted lifestyle, that means that I often replant propagules that I have bought at the farmer's market. Over the years, we have built a local seed sharing network, and I really love the seeds that I obtain from it. My valley has a strong custom of planting seeds obtained from the mega-corporations. There are a few mom/pop nurseries, and a few fruit stands that have made the effort to at least test the seeds that they are offering to see if they grow adequately here. Most of them however also sell seed that is known to grow poorly here because they are famous heirlooms: for example, Brandywine tomatoes. I typically avoid growing "heirlooms" because they were developed in far away lands a long time ago, and those are not the conditions on my farm today. I get a lot of localized seeds from face-to-face seed exchanges parties that are typically held in late winter. If you can't find an existing swap, you might consider organizing one yourself. There are lots of micro-scale seed companies forming all over that are committed to only selling seeds that they have grown themselves.

I didn't have any Emmer seeds, so I weighed a sample of my gg-grandfather's wheat variety. It contained 736 seeds per ounce. I went out back and pulled up one of the wheat plants, and counted yield. It produced 250 seeds. So a 1 ounce packet of wheat seed could be expected to yield about 15 pounds of wheat. If that wheat were replanted yield could be around 68 bushels.