i don't know much about modems. i know i want a PCI 56k modem, but when i do a search using PriceWatch, they have some that cost $7 and others that cost over $50. Why are some so cheap and others so expensive? What features should i look for to get maximum speed and performance? I notice that in some descriptions the word "fax" is included. Is this implying that i can't send faxes using any old modem (ie with fax machine from win95)??