Is it necessary to put sealants on a child's 6-year-old molars / baby teeth?

I certainly understand the importance of sealing molars. But, aren't a child 6-year-old molars baby teeth that they're going to lose anyway? My dentist has a bad reputation for gouging people where he can, so I'm always wary. At $55 per tooth, do I need to get my son's molars sealed at this point?