What is A/B Testing? Documentation
A/B testing (or split testing) consists of comparing two versions of a web page (or in this case, a price) to see which one performs better. You can compare TWO items by displaying those two variants (A and B) to similar visitors at the same time.
The test that gives you a better conversion, wins!
For more information we recommend reading The Complete Guide to A/B Testing from Visual Website Optimizer.