I would like to know if there is a site or an app aggregating the bids from the major exchanges at any given time ?
You can use coinmarketcap to know bids from major exchanges and minor exchanges as well at any given time, it is updated almost real time. If you only want to see the average of bids from major exchanges, look at preev.com and like coinmarketcap it is also updated real time. Regarding android apps, you can use blockfolio to track not just btc price but other coins as well. Still it would be a good app to use, it shows accurate profit accumulated from price movements after all.