Hi,
Which would you recommend for the health benefits, help with weight loss and water retention? (I don't need it for the full feeling or appetite surpressing) Pills or Liquid? Or does it not matter?

If Liquid, does it matter if you get it at a health food store or the grocery store? I would assume getting at a health food store (GNC, VitaminShoppe,etc.) would be better, yes, no?

I would think liquid is better. It is closer to its natural form and also a lot cheaper in the long run, if you look at its active ingredients. Plus, (usually) no fillers.
I would probably think that whatever you could get at a health food store will be higher quality, e.g. purer, but of course also more expensive.
I use the HerbaGreenTea from HerbaSway. I really like it.

Hope this helps!