Best chance at getting NBA Dallas Mavericks Finals tickets for face value?

It really depends on how the Mavs split up their ticket allotment, but your best bet is probably to try to buy tickets in person at the AAC center. The Mavs are doing a lottery there, but you'll only be competing against people who can actually physically get to the location. If you try online or phone, you're competing against people from all over the world who are trying to cash in and make a quick buck.