According to the Sales Datasheet on the website :
"The ETH price per token is 0.000278 and thus 1 ETH = 3598.214 ST. On 20 November, 2017 it was announced that all purchasers will also get 15% bonus ST after the sale due to fluctuations in ETH during the sale."

The price when crowdsale was scheduled to end was $0.13, including the 15% bonus, that's around $0.11. ETH was $460~ December 1st.
The price of ETH has more than doubled since then, the current price of OST looks fair right now. Still waiting a few days for more whale entry.