I'll recommend you to include the amount of downtime for reasons such as electricity down, Internet loss, miners acting up leading to crashes. Many people who come all enthusiastic to get into mining forget to take this into account. I was one of them. Moreover, check for the stability of the miners that you're going to buy. I'll definitely say that the price is really good for the offer but do your research before buying them and ask if he can produce some invoice for the GPUs which will make your RMA process for any GPU a less hassle in the future.