knifekits.com, USA knife makers supply, Jantz, and premium knife supply all have Bowie blades under and over $30.00. For premium knife supply also check their ebay listings. Crazy crow also has knife blanks. Also check ebay for Bowie blade blank.
In re reading your post I just spotted unsharpened. All of the above are going to be sharpened except USA knife makers supply is going to have some that are blanks not sharpened (did not see a bowie). If you want a knife without an edge you can always knock off the edge with a file or a grinder. If your just concerned about working with a knife shaping the handles etc with a sharpened edge. I wrap mine in thin cardboard then wrap the hole thing with blue painters tape for protection.