A Brevard County, FL, hospital system has been exchanging $100 gas cards in recent months for copies of bills showing what its competitors charge for certain medical procedures. Wuesthoff Health Systems says the price data it is accumulating will allow it to compare its rates for services and procedures covered by various health insurers. It says it also plans to make the information available on the Internet so that cost-conscious patients on the Space Coast can comparison shop before deciding where to have scheduled surgeries.