Most people wouldn’t be too pleased if they learned that the price of a digital camera suddenly dropped by $50 a few hours after they purchased it from the same online retailer.

Yet according to the creators of a new shopping tool called Shopobot, such price swings happen every week, sometimes every day, as retailers adopt more sophisticated techniques to test out different price points.

“The volatility is really being driven by these algorithmic approaches to pricing,” says Shopobot co-founder and CEO Julius Schorzman. “You have these automated systems that are trying to maximize revenue for retailers online.”

Shopobot, which is being backed by Google Ventures and Aol Ventures, is designed to let consumers take advantage of these price fluctuations, rather than get stung by them.

The company takes a Google-like approach to the task and crawls retailer websites, monitoring thousands of product listings for the latest prices – Schorzman says that’s a better tactic than subscribing to data feeds provided by the retailers, which he says are not always reliable.