Recently, Kris (of Anywhere But Here) recommended to me that I use Arches watercolor paper. I'm new to painting, so I hadn't really heard of them before she mentioned them.
I went to Michael's, a local craft store, and they had a sale on their Arches 140# pads - buy one, get one free. I took the remaining six pads. But I couldn't find larger paper than these 9" x 12" pads, and Kris suggested that I buy from the Internet because the paper would be unfingered by shoppers. So I hopped online and found Mister Art. I ordered a few more tubes of watercolor and not only was it cheaper than the stores (even with shipping!), it was also fast.
So a few days ago I ordered 18" x 24" Arches 140# paper from Mister Art. I got my order today.
I'm very impressed by this online store. If you need to buy art supplies, they get my big thumbs up.