It depends on the kind of app you're looking to create.
If you're okay with a "template" app, which most offline clients are more than OK with, you can easily get that done for around $200, sometimes even less. Basically, you use a pre-existing template to create your website. Since it's branded with your client's logos, colors and images, often time's it's hard to tell it's a template app.
If you want a custom app, you're generally looking at $500 to $3,000. The key here is the map out EVERYTHING before outsourcing. Hiring a programmer to create a clear vision isn't that expensive. Hiring a programmer to help you figure out your vision is very expensive. Give step by step directions and you'll have a very affordable app done.
