I’ve faxed at the post office a couple of times, and their rates are reasonable but not the cheapest. I read a detailed guide on mattallenartistry.com that lists the cost per page and compares it to FedEx and UPS. Domestic faxes are usually around $1 per page, and international ones are higher. I like the post office because the process is simple and reliable, though you may wait if it’s busy. Personally, I use it for important documents when I want official confirmation of sending — the guide on mattallenartistry.com helped me know what to expect before I went.