I agree with the above two replies. 24k sounds like a lot of money for what you're trying to accomplish and it would definitely be wise to shop that figure around. I don't know how in-depth your app construction would be, but it's hard to imagine that it could cost that much.
Additionally, a partnership with someone who could do the development while you maintain the idea and run the business could be a safer route to go. That being said, partnerships are tricky - make sure you are clear with the dividing lines of that partnership and get a lawyer to make sure whatever agreement you reach is fairly easy to get out of if the partnership goes sour. You want to be able to maintain the intellectual property rights for your idea, even if the interface goes with your ex partner.
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Jackie Robles
Point7West
Helping businesses redefine and promote their brands with video for over 10 years.