I usually wait till something goes on sale and then I buy a bunch.  Lately the local grocery store has had very lean London broil on sale.  I just pulled the jerky off the 
dehydrator this morning (5 lbs before dehydrating).  You can use just about any lean meat that doesn't have a lot of marbling of fat in it.  Round Steak, eye of round (I don't really care for eye of round, but it goes on sale a lot), London broil is probably my go to when on sale.
I usually toss the meat in the freezer for about 30 minutes to an hour to firm it up and then slice it in 1/8" slices myself.
Marinades... no end to them.... I usually stick to the following and I judge how much of the ingreds ast to the amount of meat I have.
Light Soy sauce, Worcestershire sauce, red wine vinegar, honey, brown sugar, raw cane sugar, onion powder, garlic powder, Tony's seasoning and sometimes I use a bit of liquid smoke.  Marinade times will differ as well.  I go for 12 hours minimum, but you can go more or less on how much you want the flavors.
I have tried using a smoker for drying, but prefer the 
dehydrator as it is more efficient in my opinion.