1000USD for 30GH/s cheap?
ROI infinity...
Bitcoin could go up to 10k.... and if the person mines .5 bitcoins (somewhat questionable) then they'll have 5000 dollars...
Weirdly enough there is still a lot of potential with bitcoin. The person would have to be extremely patient.
It is good to point out that it makes no sense to buy one of those right now. If you thought the price would get that high, you'd just by one bitcoin.
It is not worth buying 65nm ASICS either... 28nm and 14nm are the future... 28nm make sense because it's close to the final jump that will happen quickly. 14nm is probably going to have a lot of delays and by that time the mining reward may have been halved.