This has been beat to death and recently. Please read through the forum, you will get all the answers you need.
It is a bit too late, as OP has already bought the ASICs "cheap" off ebay...
On the bright side, he is mining for fun.
However is there any profitability with mining? I'm seeing people say that even the S1's are no longer retuning the ROI.
Sorry to tell you, but I don't think you can get ROI at all, unless you get extreme luck in solo-mining...