I just use Healing Spring Water. Buy hundreds of bottles, head north of the bridge north of Gran Soren, and fill them all up then distribute amongst your party. they heal your entire party for a good amount.
Well I don't know what the best ones are but, I like keeping a few spring water bottles with me wherever I go in case I need them. I really don't carry many curatives, just work with what I find in the field mostly. Spring water doesn't heal that much but, heals the whole party and all you need to do is go to a healing spring and fill some bottles, I have over 100 in my stash.
what they said, i wouldnt say its the best healing item there but its the cheapest and easiest to get, also pretty dam useful. just buy a ton of empty flasks, go to the spring, this is the part that takes some time, fill them all up and distribute. easy.