$data =~ s/ss^\b/ran("55","\$\$","\$\$")/gie;
That ^ makes no sense.

He's trying to make "$$" a more probable outcome than "55"... if you have a bag with one red hat and two black hats, and you pick one at random, chances are better for picking a black hat than a red one...
I kinda like the way he did that... it's strangely creative :)