Is it possible to mine others currency on our choice? using our own pool?
Also the price for 10 GHs is 9.99 USD, is this one time payment and for how long it last?
You can mine other types of currency like LTC, Doge etc, but only if you buy a Scrypt contract. You can not choose your own pool.
If you buy a SHA256 contract then you can mine only BTC.
It is a one time payment although there is a daily fee of 0.01 USD per 5 GH/s that it taken from your daily payment, so that's basically 0.02 USD if you have 10 GH/s, and the contract is for life.
If you purchase a scrypt payment then the daily fee is 0.08 USD per MH/s.
Any other questions, just ask and someone from Genesis Mining or myself or another forum member can try and help.
Ian