Walmart, eBay and Amazon are actually decent sources for calligraphy supplies. Walmart also has "paint pens" which are essentially markers with paint in them that lets you have much finer precision than a brush. You can even cut the tips to them if you want, and they run about $2 each.
Wax, I'm not sure, but any candle place should have it, I'd think. As for seals, if you want a variety for reasonably cheap, leather stamping tools will work.