Is it considered good business practice to reveal one competitor data to another in order to get a better deal?

YES IT IS NORMALLY DONE IN THE BUSINESS AND IT IS VERY VERY USEFUL IN GETTING THE DEALS WITH MY PERSONAL EXPERIENCE, IF U HAVE A NON DISCLOSURE AGREEMENT SIGNED, THEN IT CAN LEAD TO LEGAL ISSUES.

It is bad practice to provide confidential information to a competitor. This is unethical but common in practice. By doing this your suppliers once aware of it will no long want to deal with you and eventually you become a victim of your own deceit. Without an open and competitive environment you no longer know what the market rate is for the supply of a product or service. Bad outcome.

If you have a Non Disclosure agreement signed, then this is a bad idea. THis will be considered un ethical, and may have legal implications