Here is an activity that I originally found in the book Math for Smarty Pants :
What are $1 words? Start by assigning a cent value to each of the letters of the alphabet. Let a = 1 cent, b = 2 cents, c = 3 cents, and so on up to z = 26 cents. For any word, add up the cent values of its letters. If they sum up to $1, it's a $1 word. You may want to verify that "maximize" and "reciprocal" are $1 words.
In English, there are several hundred $1 words. If you want to check the value of a word, I have a one dollar word value calculator available. You can also view a (fairly complete) list of $1 words. This list contains nearly 1,000 words (966 words, to be precise), some of which are proper nouns.
Before you take a look at that list, though, here are some questions to try:
In case you're interested in words that are $1.10 words, you can find a list of them here.
You may also like math activities for kids and other word-related mathematical recreations.
Sources used (see bibliography page for titles corresponding to numbers): 32.
One final note: Of course, assigning values of 1¢ to 26¢ is somewhat arbitrary; one could assign other values, say $1 for an a to $26 for a z; in that case, one might be interested in finding "hundred dollar words."