From what I can see, the type of black glasses she would like to wear from time to time is called nerd glasses, which has been very popular in the world. Anyway, as a matter of fact, those nerd glasses could be found at every large optical centers including Walmart vision center or Lenscrafters which is also a great place for nerd glasses.
It is the small black eyeglasses that chelsea houska wears. You could go to the online stores to search the similar type from the design and the color. First of all, you should see whether this type of glasses is suitable to you. Then you could just go to the online stores, like amazon and walmart to search such type. The price there will be suitable.