There's always a cheaper way to do something, but it's important to remember that 'lower price' often doesn't mean 'lower cost'. In order to get the lower price you need to spend on whatever the alternative option isn't doing in order to give that price saving. For example, moving from AWS to onprem means you need to configure the infrastructure yourself; you save on AWS fees but you spend more on devops. And then you have to factor in things like the cost of downtime (on both sides of the equation, especially if you use us-east-1), the price of building your own services, the price of software you need to buy, and so on.
You only save money if the differential cost based on all the factors is lower. AWS is expensive for some things so it often does save some money, but not always, and if you haven't done a proper analysis you can't know.
You only save money if the differential cost based on all the factors is lower. AWS is expensive for some things so it often does save some money, but not always, and if you haven't done a proper analysis you can't know.