Glad you asked. http://blogs.wsj.com/independentstreet/2009/01/28/in-n-out-burger-vs-mcdonalds-guess-who-won/
https://www.google.com/search?q=in-n-out&safe=off&source=lnms&tbm=isch&sa=X&ei=hF0KUuHbI-G2igK6wYCQDg&sqi=2&ved=0CAcQ_AUoAQ&biw=1144&bih=1006
A cheeseburger, fries and soda costs just over $5. Starting pay is $11. They're serving more customers at 3:30 in the afternoon than most fast food restaurants are serving at 12:20 in the afternoon. At lunchtime, I will count about fourteen employees working in an In-n-Out.
They never freeze any ingredients. They have no microwaves or freezers or heatlamps. Potatoes are sliced from whole potatoes at each store. They have the freshest fast food you'll ever eat.
So In-N-Out may be higher quality but it's certainly no cheaper. McDonald's is 3.00 plus tax for the stuff you mentioned. The McDonald's I live near gives out the small cups for free, so I pay $2.00 for a McDouble and fries. I think that all McDonald's are obligated to give you a cup of "water" (which you can fill with anything) for free.
Besides, I think that I said in my original post, that if such a company existed they were not nearly as efficient. McDonald's, BK, and Wendy's are all much more popular than In-N-Out, so arguably In-N-Out is not nearly as efficient.