Blockvila pays you 10% per month for buying a mining package with it. Payouts are sent every day(of course after deducting the maintenance fees). At the end of 6 months, you have the choice of opting out of the contract. You can then resell your miner at a 10% discount rate to get 90% of your capital back. But if after the full course of a contract(i.e 24 months) you want to resell your miner, you will do that at a 40% discount rate. This is so because something that you used for 6 months and 24 months is not in any way the same.