Hashing power in WariHash is currently priced in BTC / Terahash/sec / hour for the SHA256d mining market. To be precise, the price is the amount you will pay in Bitcoin for renting a machine with a hashing power of 1 Terahash/sec for 1 full hour.
Other markets will use the same pricing method but may use different units for hashing per second (i.e BTC / Megahash/sec / hour )
You specify to buy 10 Terhash/sec for 1 hour, and pay at a price of 0.0001 BTC /Terahash/sec/ hour. You will end up paying approximately 0.001 BTC (0.0001 * 10) .