Mostly on reviews of a bait, and whether or not they fit into my fishing style. For instance, I like to fish shakeyheads, and when I read the article on the Hag's Tornado I ordered a couple of bags. It quickly became my favorite soft plastic for that, so this year, I ordered several more bags.
Over the years, I've never listened to what a pro was pushing in the way of lures.....until KVD came along with his RedEye Shad and the Sexy Shad color. I've caught a bunch of fish on that lure and it remains my favorite lipless crank. I also listened when read about shallow running square-bills and now throw those in place of spinnerbaits most of the time. Thanks to a gift certificate I got this year, I now have several of the new KVD 1.5 and 2.5's and have high hopes for them.
As for price, let's just say that $7+ spinnerbaits give me a pucker factor of +10, not to mention $15 cranks. If you like 'em and can afford them, drive on, brother. As for me, I stick with Bandits, Bombers, SK's, and a couple others. Heck, I've done very well on BPS copies.