Depending on the scale and other factors, it could be anything from $25000-500,000! The most important factors a SaaS development company in the US or a founder building SaaS would quote are:
Team location/Geography: Where you get it built matters. The cost may vary significantly whether you hire your SaaS application development company from Eastern Europe to India to North America.
Product comprehensiveness and features: How complex and comprehensive the SaaS will impact the cost.
Hosting infrastructure: The platform you are hosted on and the traffic would impact the cost dynamics quite dramatically.
Security and quality testing: The investment you do in thorough testing and the kind of security practices you follow may have a big say in the cost.
Maintenance and support: Whether the SaaS product needs a huge support team from the SaaS development agency or individually or can be run with the least support team will impact post-development cost factors.
As a SaaS product development company, we understand the complexities that a SaaS application development project may bring. And for that reason, we always follow an incremental progress methodology to reduce and optimize the SaaS software development cost.