Pricing is about two things.
1) Covering your costs.
2) Positioning.
Some people will say COGS s/b about 30%, and that's a good starting point, but what is YOUR expertise worth? Price accordingly. Price for quality of product, ambiance, training/expertise, service etc. If two coffee shops are sourcing the same exact beans from the same roaster, one will likely charge more than the other. Why? Their drinks are worth more. Understand your (shop's) worth.
Generally have about $.30 to $.50 between sizes on your drinks. I would do a quick stroll/drive around the area and check out a couple places to get a feel for the pricing. Decide how you believe your overall product fares in comparison and price accordingly.
syrups ? .25 per pump or .50 to add to any size.
Soy, almond milk, half/half (breve)? $ .50 Why? It's not normal, that's why. It's a latte, it's made with cow's milk, that's what normal people drink. Want us to stock something else? Sure, but it'll cost you. ... Honestly, that's pretty much why. It DOES cost more, and that's part of it, but in the end it's about establishing norms in your shop.
How many shots? There are two schools of thought. (Actually there are three, but the other one doesn't count) One is: Start with a double shot at eight and twelve ounces and a triple for 16. 20? Don't make a twenty ounce drink. They are not cost effective and nobody who actually wants espresso will get one. We've been around for going on eight years. 12 and 16 ounce for the longest time, eventually we added an 8 oz. Every decent place I know has dropped their 20 ounce, or never had one to begin with. Just don't.
The other is to do everything standard double shot, and people can buy extra shots if they want more. That's what we do. Those who get smaller drinks want to taste the espresso more. It's a different kind of person who gets an 8 oz. latte and a 16 oz. latte.
No coffee should be going out your door for less than $3 per cup. The days of the $2 and $2.50 cup should be over. Buy coffee that warrants it. In this day and age there is no reason to be serving people gas station coffee. Take care of your customers by sourcing the best ingredients you can find! Ethiopian's make some damn tasty food. Do the coffee proud as well!