What to look for in a trainer?

So my husband owns a marketing firm that does SEO for both local and national companies and one of our new years resolutions is to see how much we can get through the barter system. So we contacted a few local personal trainers to see if they would be interested in trading SEO for coaching and all of them are. What should we look for in the initial contact and website? Is there anything that we should stay away from? I know that one of them sells shakes and the like, so should we even consider her if she's involved in that kind of stuff? I want to continue to work hard and bust my butt to get to my goal, not be plied into drinking a shake like that will change everything.