Altcoin can be valued much lower than 1 satoshi. Sprouts is ranked 152 on Market Cap and 496 on 24 Hour Transaction. But its value is 8.027e-09 BTC as on 13th of September. It was valued higher and it dropped.
When you talk about value, you have to compare it to something. If you compare it to something that has a fixed value (i.e. Gold), the value of it would be determined by the market, which in turn would be determined by the policies around it (if it becomes a legal tender, the demand would increase). If you compare it with currency (take any currency which is not Gold linked), the value even if stays steady, would mostly go up as the currency itself is de-valuating (like the US dollars). You can never know the position as there is no thumb rule to know that.
Think of it as a penny stock investment. The thing can become big and give you multi-fold returns or go poof.