We do get queries along the lines of "Why will i update a price and the next week it is gone to $0.00". We have to find a good balance between conflicting goals here:
- Display accurate prices
- Constant price data
- Feedback on user input
After 2 or 3 days, a price is normally too out of date to give any meaningful information for comparing stations in a given area. For this reason, after that time we stop showing that price. By coming up as 0.00, this also alerts other users that this station needs to be updated again.
We start showing the age of the price in days to give people a bit more information on this as well. If the price is still accurate, you should be able to just tap the "These prices are still correct" button and we'll reset the age stamps on those prices.