We too have both. I shop at local stores and purchase numerous styles and sizes of ceramic mugs. the biggest issue is how many oz. in the colorful conglomeration of mugs. I take mugs and measuring cup to water fountains before buying. Big lots, dollar stores, Ross and Marshalls-all have fun and funky ceramic mugs for reasonable prices. When you pay around $1.00 a mug, it is way cheaper than carry-out.
It has become a trade mark of our shop, and I've heard customers comment on how neat that all the cups and glasses are different.
for take out, we stock a thin foam cup, 12, 16 and 20 oz. one lid fits all. you have to order at least a case. this is nothing like the fat styrofoam cup.
for in house, we only call the cups sm, med and lrg. lattes and mochas go in 16 or med. house coffee gets free refill, most people don't care that much about the exact size. I try to keep about 75 cups on the shelves.