We have one of the round nesco (?) ones we got from Walmart about 15 years and it works fine for small batches. Hell we still use it along side our shelf dehydrator bc we do a ton at once. Sometimes the bottom trays can dry faster so you might want to rotate them around a few times. For the $50 we spent on it, it's been great.
I make jerky with wire racks and a fan blowing over it. I can typically get it done in 24-36 hours. They key is to salt it and let it sit in the fridge overnight to let the salt penetrate into the meat. Letting it dry at room temperature isn't going to be a food safety issue.
Use toothpicks to hang the meat from the oven racks. Line the bottom of the oven with foil just in case. Turn your oven on its lowest temperature setting. Crack the oven door with a fan nearby to provide circulation. Wait a few hours. Profit.