Do you have Photoshop? I once "reverse-engineered" Sep Studio by using the Calculations feature in Photoshop in RGB mode and discovered that Sep Studio is basically a fancy script. If you are a bit intrepid with PS and have a demo version of SS you could figure it out.
With that said though, I think Sep Studio can be very helpful if you understand its strength and weaknesses. If a piece of art comes to you that fits the software's color palette, great! You can have pretty damn good seps in minutes. On the other hand, if your art is color-critical, or it has lots of subtle gradations in tonal colors, it may not perform as well.
I've always thought that SS would be very powerful if you could sell a product with the caveat that the print will look good, but it may not match the customer's original art. You could save so much time by using it as a piece of automated software. Doing the Calculations "by hand" (so to speak) in PS takes a few minutes, and you'll have to spend some time on the front end trying to figure it out.
I also have to agree with davidshaw that accurip is awesome.