Cloud providers may not always fulfil the Service Level Agreements with the clients because of outages in the data centre or inaccurate resource provisioning. Minimizing the Probability of Failure of the tasks that are allocated within a Cloud Infrastructure can be economically infeasible because overprovisioning resources increases the cost and is economically inefficient. This paper intends to increase the fulfilment rate of Service Level Agreements at the infrastructure provider side while maximizing the economic efficiency, by considering risk in the decision process. We introduce a risk model based on graph analysis for risk propagation, and we model it economically to provide three levels of risk to the clients: moderate risk, low risk, and very low risk. The client may decide the risk of the service and proportionally pay: the lower the risk the higher the price.