Glass Measuring cups are some of the most used tools in my kitchen. They don’t just measure. I use them to melt butter or chocolate in the microwave, heat soups and sauces, mix small batches of batter for pancakes and waffles, and anything else you would need a small mixing bowl for. I have them in 3 sizes; 1,2,and 4 cups.
My favorites are the Pyrex brand, but those are getting hard to find in glass. This one is probably 35 years old. Did I mention they are really durable? The other brands work well, but the markings tend to eventually wash off.
One can find them in almost any store that carries kitchen equipment for less than $8.00.