Both an MVP and a prototype are meant to test out a hypothesis. However, with a prototype, you won’t get anything more than feedback. An MVP, on the other hand, has to fulfill the primary function you envision for your product, it should be able to collect valuable data from actual user engagement. Whether we choose to build a bot, web app or native app will also affect the cost.
So how much will it cost? Whilst every startup I work with is obviously different, I like to give a guide as to the kind of costs you can expect. If these are in the right ball-park then get in touch and I can offer a more personalised quote.