I made jerky from store bought roasts on sale for years. Have the meat department slice it around 1/8th inch thick, then trim off the fat. (I worked next to the store, I would select my roasts about 10am and pick it up after work, to make it easier for the butchers)
I soaked for 24 hours (refrigerated) in sugar, salt, liquid smoke, and black pepper. Laid out single layer and dehydrated for 36 to 60 hours, turning every 12 to 18 hours and consolidating as you went. Put in freezer bags when done and kept frozen until needed. Easily good for 10 days to 2 weeks after thawing.
This is with RAW MEAT! I wouldn't try with pork or poultry. ON them use a smoker.
We started with 2 of the Ron Popel dehydrators they lasted 3 or 4 years then switched to a now discontinued brand that were 4 trays each. 4 trays each is about the limit on small units. But since you are adjusting and consolidating, you can usually start the next 4 trays in about 2 days. We had 4 of the same unit (16 trays). That worked well for us. Cabela's has a big selection of models in store and bigger online. We tried the Electric Oven method and found it not feasible! I tried building my own using 100W light bulb (Easy-Bake Oven), also not feasible! Be sure you have a blower or fan in it, cuts time in half!
We did lots of dried apples and pears, as in hundreds of them! Cored and sliced thin (not pealed!). Single layer and 4 trays in 2 days.
Hints: Cleanliness in not only next to Godliness, it keeps you from getting sick! Most of the drying tray's won't fit in a standard kitchen sink! They need hand scrubbed not dishwasher so get a tub to soak and wash them in from the beginning! Fruit and some marinades are super sticky. we made cloth nets to line the trays with to help in removal. They were bagged and washed on delicate cycle after every batch.
Liquid Smoke brand name is very expensive! I would buy GFS or other commercial brands by the gallon for what 8 ounces of brand name would cost.
All my dehydrators came with recipe books. Internet recipes are very subject to scrutiny! Both salt and white sugar are preservatives, I would never trust a recipe without one or both! (Maple syrup and Maple sugar are very tasty, but not a preservative!)
Ivan