To my knowledge, this is very much an open research issue.
Here is a paper by Prof Leslie Smith, an acknowledged expert on neuromorphic perceptual coding, which explains the importance of the notion of perceptual time for Artificial General Intelligence and sketches an architecture from which a notion of 'now' might emerge: Perceptual Time.
I don't know what kind of price data you're dealing with. I suppose the order of the data matters a lot, so my suggestion would be:
Use LSTM as it handles time series better
You can predict 3 consecutive numbers from an RNN as the next three days' predictions
Try regression first, it is likely it will not work (or just flatten the curves, depend on your ...