I wonder if I were to pay an outragious amount of money to place a banner on a large corporate site, would the amount spent on the ad bring in profit? Through my own experiences I noticed that some sites that do not charge a lot actually bring in a ton of traffic whereas some sites where I had paid a bit of money like Bravenet turned out to be a loss. But I never put a lot of money in a corporate site like a frontpage Alexa ad and was wondering if it would be profitable. Any advice would be great and thanks for reading :)

Probably not; it's far less risky, if you want to try advertising, to go for smaller niches.

have you tried stumbleupon? its the first time i used it yesterday and for the price it works great.