Ask for detailed costs based on wireframes to different agencies for Upwork Clone App. Once you will ask for a quote from your local agency, IT consultant or Freelancers on a marketplace like Upwork you will get a variation on the number($). it will depend on the following factors:
Location – Where you are looking for hire i.e USA, India etc.
Technology Stack – Which technology stack you select to develop your idea i.e MEAN stack, ROR base solution will cost much higher than PHP and CMS base solution due to lack of skilled professionals in the respective category.
Third Party solution – In your proposal somebody will suggest third-party scripts in order to develop some of the features which ultimately reduces the cost but it will have its pros & cons.
Timeline – If you want a fast turnaround of your portal to market in the competitive timeline then you have to hire multiple resources or a team so it can affect the budget.
Deployment – Nowadays cloud based hosting is so popular which charges based on bandwidth used so you need to be very sure that if somebody recommends AWS or google cloud hosting then you should ask your provider about test performance so you can get a rough idea about the server cost.