Hey Buddy, I've been developing apps since 9 years so I think I can answer your questions -

1. Hire a development instead of an individual, companies are more accountable, have teams, fall back plans and can handle multiple technologies and tasks (like design, front end, backend and so on).

2. Cost depends upon features you need, it can start as low as $ 1500 if you hire an offshore company like us, you may also try calculating some cost range by selecting options and describing your idea on this app cost calculator - https://www.agicent.com/app-development-cost-calculator

3. Timeframe depends upon features again, though none of the apps I developed in past took more than 10 weeks as for first set of features. The more features you want to involve, the more the cost and time goes up.

This old post might help you as well - https://www.agicent.com/blog/how-to-hire-app-developer-successfully.

Thank, me later. )