SysML is a prominent standard serving model-based system design for systems-of-systems (SoS). It facilitates the description of complex system design, as a hierarchy of interacting system components, while at the same time enables the independent description of each component behaviour. However, in order for the system designer to decide whether a SoS architecture is efficient, non-functional properties, such as performance or cost, should also be taken into consideration. There are numerous efforts integrating performance properties into SysML models and their verification using stochastic or analytical methods. In this paper, we focus on the financial assessment of SysML models, estimating economic attributes of SoS architectures, such as Total Cost of Ownership (TCO) and Return of Investment (ROI). Integrating different viewpoints into SysML SoS models, focusing besides structure and behaviour, also performance and economic attributes, enables the system designer to explore alternative solutions for system design, having in mind a wider perspective of the system under investigation. To this end, a profile extending SysML to serve techno-economic analysis of systems is introduced. As an example, the Total Cost of Ownership (TCO) for cloud infrastructures, modelled as SoS is explored. TCO properties are incorporated into existing SysML cloud models, enabling the designer to compute TCO for the whole system or parts of it.