Check these out. I ran across them at a gym yesterday. They're from a company called “US Wellness Meats” and they run about $3.50 (half as much as you'd pay for a sandwich).
They are a combination of grass-fed beef jerky, grass-fed tallow, touch of honey, dried cherries and sea salt, which is advertised as a “tried and true historic Native American recipe”. Each bar contains 20 grams of protein and 380 calories. And zero preservatives.
I approve. So for those you looking for a low-carb afternoon meal, there you have it.