McDonald's is just an example. Presumably when we are talking about one company paying a living wage we are talking about all of the companies in their industry doing the same. Then again, starbucks pays well, has health insurance, etc., has high prices, and is killing most of their competition...so maybe not.
Also, the rise in prices doesn't have to be that large to cover the increase in pay.
"From that humble start as a small restaurant, we're proud to have become one of the world's leading food service retailer in 118 countries, with more than 34,000 restaurants serving nearly 69 million people every day."[1]
So an average store would serve ~2000 people a day. (69,000,000 / 34,000 = 2029.4)
I don't know exactly what the workforce looks like, but it's probably something like 4 cashiers, 2 cooks, 2 helpers, and a manager. If we assume we don't need to pay the manager more then that's 8 employees per store that we want to have a higher pay.
The big mac value meal is $5.69. Let's say the average customer buys that. [2]
2000 customers per day * $5.69 = $11,380 in revenue in a day. I'd bet it's more, but that's a start.
If we have 8 employees working for 16 hours a day (different employees at different times, of course), and we want to raise their wages $3 per hour, how much more do we need to charge?
Well, if we want to keep our profit margin the same then we'd need to earn an extra (8 employees * 16 hours * 3 dollars) $384 a day.
So, we'll need to charge each customer $0.20 more per order. ($384 / 2000 customers per day).[3]
So, really. Is changing the price of the big mac meal to $5.89 really going to change McDonald's market position? Is it going to make eating at mcdonald's that much more expensive that people will stop going? Is there any real impact on anybody but their employees?
I'm sure there's an error in those calculations somewhere, but the general idea is that it doesn't take much of a price increase to cover the pay for employees.[4] This is what drives me crazy about these companies. Walmart moves so much merchandise that if they raised the prices on all of their prices by a nickel they could probably afford to pay everyone a living wage.
[1] - http://www.mcdonalds.com/us/en/our_story.html
[2] - in the USA, of course.
[3] - there may be some other costs to paying employees more for the business, but I can't think of any off-hand. Also, the amount of tax collected per transaction would be higher as well, so not only does society benefit from having less people on public benefits, but it takes in more money overall that it can use for other things (in places where fast food is taxed, of course (is that everywhere?)).
[4] - Another problem with this simple calc is that not all stores are average and many don't do anywhere near 2000 customers a day in business. They probably employ less people, but it's something to keep in mind.