Well, it depends on what you want the insole to do.
If you just want to add padding/make your shoe fit better, I recommend the super cheap drugstore white foam ones. They do wear out so you have to replace them (maybe once a season, more if you wear the shoes a lot). You have to buy a different pair for each pair of shoes. Like this:
http://www.cvs.com/shop/produc.....uId=489145There are also gel ones if you prefer that. (I don't like them though)
If you actually need arch support, you need to get a hard, structured one. They cost around 20-40 dollars and you can get them at sporting goods stores or online. They last a long time, and I switch them between shoes so you only need one pair. I like superfeet and powerstep. For example:
http://www.amazon.com/Superfee.....38;qid=136I often use both of these types (in one shoe) because I have flat feet (hence the arch support) and I also like the extra padding from the foam. I dont have problems with sweaty feet but then again I ALWAYS wear some sort of socks in closed shoes. You can't put insoles in sandals anyway. Anyway, I suspect the first kind (the cheap foam ones) would actually absorb sweat (Odor Eaters are this style too, if you wanted to reduce foot smell from the sweat.)
