There are a number of approaches to measure price sensitivity, ranging from a focus on individual products to those that can be used to model a complete portfolio.
At the single product end of the scale sit Gabor-Granger and van Westendorp. van Westendorp is preferable if people might use price as a proxy for quality (e.g. Jewellery).
At the portfolio end of the scale sit Conjoint approaches (see also New Product Development and range optimisation above) that can investigate price sensitivity within the context of portfolios and competition.
Outputs are usually price demand curves and simulators that allow you to explore thousands of possibilities.