One of the many reasons Cloud solutions are so attractive is because of the substantially lower capital investment costs to implement them, when compared to building your own solution. Many vendors are willing to give away equipment & services initially, knowing full well that once you're in their ecosystem they'll get their money back, tenfold. How can they be so confident? Well, generally because it'll cost far more than your agency can ever afford up front in order to leave their ecosystem/solution. That's their business model.
Those that know me know I'm a big fan of Cloud-based solutions, from storage to Software as a Service (SaaS), and more. That said, regardless of the solution you should always consider all related costs of ownership prior to implementing it, including any cost that may be incurred years down the road when your agency needs or wants to move away from a particular solution or technology.
Maybe you'll be retired when the time comes for your agency to try to move on from that cloud solution you implemented. Unfortunately, unless you're six feet under...you'll still be paying for it via your taxes. Just a heads up my friends. All the best.