Helen....I use an Epson Stylus Photo RX 500 All-in-One, so I use Epson Premium Glossy Photo Paper mostly. Many say that you should use the Photo Paper recommended by your printer manufacturer but there are other great papers around that give good results. I occasionally buy my photo paper from Asda (Georgia Pacific brand) if I run out of Epson and I buy GP acid-free paper and cardstock for journalling and photo mats too. They do a pack with Earthtones, which is pretty useful with most coloured 12 x 12 cardstock+ I also buy white. Both sell for under a £5 and last ages.
The acid issue is particularly relevant to your processed photos as the acid in paper, card, adhesives, etc. can migrate and cause your photos to deteriorate quicker. If you are printing your own you should take similar care of them but I don't think that everything available tells you if it is acid-free or not. There lies a bit of the problem! Buy a Marvy Uchida Neutral 7 Acid Identifier Pen if you can! If you make a small mark on the back of what you plan to use it will give a reading....with 7 being Neutral PH. That is best case scenario :o)
Hope that helps, Marilyn (posting via google as the servers are slow tonight)