I remember reading about a scheme for doing this in a childrens' cryptography book when I was a kid. Choose a ten-letter word with no repeated letters, and use this to represent the digits 0-9. I think the example from the book was REPUBLICAN, but there are surely plenty of alternatives. Using this word, you'd get
10.71 = ERCE
250.22 = PLRPP
This is pretty easy to break--if I saw it in a store I think I'd probably be able to break it in my head with a little work (figuring out the first digit of prices shouldn't be so hard.).
You could make it a little tougher by having some null letters which have no meaning, and using them to make labels that are harder to decode. Suppose your nulls are JQXZ. Then you could have
4.22 = JBPXXPQ
You could also use fixed length "words" and have only some letter positions matter, or use two different ten-letter codes, or whatever. You won't ever get a really strong cryptosystem out of it, but if you're not trying to sell stuff to a convention of cryptographers, some scheme like this might work okay.