No amount of advice will replace a little cost analysis. Get the price of a sheet of silver in the gauge that you normally use (pick a size like 2"x6"). Figure out how many disks you can cut from that sheet, keeping in mind that you need a little space between the disks. Now, figure out how much it will cost you to purchase that same number of disks pre-cut. Calculate the difference between the pre-cut disks and the sterling sheet. Divide $265 by that number and you can figure out your break-even point, the point at which you've saved enough money by cutting your own disks to have paid for the cutter.
Keep in mind that you can recycle the scrap sterling for 90% at G&S Gold or Midwest Refineries, and that having the cutter gives you the flexibility to offer thicker gauge disks or other sizes if a customer requests such. You can pre-sand and -polish the entire sheet at once, which is much easier than doing one disk at a time, so that's a time saver :-)
Also, if you get the Swanstrom, you can pick up these little goodies that allow you to make sterling ring washers, which could also be used to expand your design line.
http://www.riogrande.com/MemberArea/ProductPage.aspx?assetname=112524&page=GRID&free_text=swanstromDo some research on the Pepe vs the Swanstrom. This is one of those cases where you buy the best tool that you can possibly afford.
