Spice and Velvet are really expensive though, I prefer to trade linen (buy from Sargoth usually, sells well in most southern towns), salt (usually from Khergit towns), and iron (I think this tends to be cheap in eastern Vaegir towns). In the first few weeks of the game, prices usually haven't found their natural level, so trading isn't always successful early on. Once the economy has sorted itself out though you can make plenty by going for these relatively affordable goods. Once you get really rich you can buy spice and velvet, but often the place your selling them at will run out of money quick because they cost so much (spice and velvet can sell for around 1000 I think).