I used sliced beef liver in my Excalibur dehydrator. Beef liver is really cheap, at least around here. I don't marinade with anything, and it usually takes 36 hrs to dehydrate fully (outside on a humid day). I keep the resulting jerky in a ziploc in the fridge, and my 18lb Jack loves it! Also, you don't need to use very big pieces, so it'll last a heck of a long time. If you're going to use your oven to dehydrate, use the same process as beef jerky, which can be found online.
If you're not going to marinade, I would recommend keeping the jerky in the fridge, because you're not curing the meat, as would happen with people jerky.