Looks like he's wanting at least $70 apiece for the S3s, and probably $40-50 for a PSU that'd run both of them. That'd get you about 880GH for a little over $200 shipped within the US. He's got 4x S3 and two PSUs here.
Would he split that to 100 even? for one of them ?
Not a damn bit of my business, but if you can swing $100 try to swing $200 and pickup that deal. Close to 900GH/s turn key to your door (with relevant miners) is not bad at all. If you want to really learn mining you may want to go a different route. I say this because I am a moron and managed to get 12x S1's running without breaking anything or screaming or crying or really any mistakes. I had my S5's unboxed up and running in 5 minutes. Bitmain products are awesome like that.
If you wanted to dick around some more get some miners that need cgminer or similar and raspberry pi. If you are an enthusiast/geek you'll likely have more fun going that route.
(list to others over my advice)