$80 Suzuki student violin is fine for elementary school music. Believe me, for your 4th grader, it's just a bunch of screeching, not matter how much you spend.
That's what many school districts use, and rent to students for $20/month.
http://cgi.ebay.com/1-2-Violin-Fiddle-Free-S-H-Suzuki-Teacher-Approved_W0QQitemZ130159045102QQihZ003QQcategoryZ3 8110QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
(This particular one has crazy shipping charges, but you get the idea).