Here are some of my favourite tools with links of where to buy them:
There are two papers I always recommend for calligraphy practice. The first is HP's 120gsm ColorChoice printer paper. This is what I print my worksheets and practice paper on. It's perfect if you have the space for a big pile of paper at home, and if you're going to be printing practice templates or worksheets at home.
I also love Rhodia pads, which are another option with a high quality, exceptionally smooth finish. The pages are perforated, and this is a great option if you don't need to print on the sheets and you don't want your supplies to start taking over your house (yet!).
My favourite basic ink is black sumi ink. I find that it performs well on many different papers and with many different paper, and I prefer it to any other black ink I've ever tried.
The nibs I supply in my calligraphy starter kits are Zebra G. You can generally buy them from all online calligraphy shops (e.g. Scribblers, Blots Pens, Penman Direct), but if you shop around you can sometimes find some good deals for packs of ten.