The range is immense, from $2,500 to $50,000 and more. A small, simple contract for two parties may really cost you less than $3,000. But if you need a complicated program for multiple users, expect the cost to rise with each sophisticated element.
The final cost also depends on where you look for smart contract developers for hire. If you choose to hire in-house specialists for the project, expect additional payments such as insurance, paid vacation, etc. You can also choose staff augmentation, which will cost you much less.