My son, Nathan, has been begging me for a thesaurus. I donated ours years ago because it was never used. They are just so bulky, and if you are a bibliophile or homeschooler, you know how precious bookshelf space is. Michael Clay Thompson of Royal Fireworks Press recommended buying an electronic thesaurus.
I bought Sharp Electronics PW-E550 Electronic Dictionary, and Nathan has been using it regularly. He has taken it in the van with him, into restaurants, and used it when typing on Microsoft Word. It also contains a dictionary which is a bonus! I like the fact that it is small and super portable -- it can be brought into the kitchen for writing class, back to his room during his creative writing time, or even in a restaurant without much hassle.