Hi Manaswini,
I see at least 2 options:
IF(ISNULL(PRICE), 0, IF(ISNULL(FCST), 1, 0))
OR
IF(ISNULL(FCST) AND PRICE > 0, 1, 0)
--> here i assumed that when there is PRICE, it is higher than 0. If you want to include also 0 case you can build it like AND (PRICE >0 OR PRICE = 0)
Regards
Alecsandra