I use this artistic wire for some of my jewelry.
http://www.firemountaingems.com/shopping.asp?skw=KWCORDZEBRAWIRESILVER I haven't had a problem with it tarnishing or flaking, though I'm using a 26g wire and only use to to wire beads to components. It is very soft though and I haven't tried hardening it so don't know how it will respond to that. But its inexpensive and good quality if soft wire will meet your needs.
But if you find a good source, sterling silver doesn't have to be too expensive. I just bought about 30 feet of sterling silver 24g wire from Santa Fe Jewelry Supply for about $25.
Also, while Sterling or even Silver-filled does cost more, you can also charge much more for your product. And, you can recycle your sterling and silver-filled scraps and get some money (or store credit) back to put towards buying more wire.