Employees (Express, at least) get 16 passes per calendar year. Each pass is good for "one way" travel with up to 3 segments-- beyond 3 segments requires another pass even if travel is continuous. Price is charged based on origin/destination, not per-segment.

Rates range from $50 for short haul to $80 for long haul domestic US/Canada/Mexico/Caribbean. Travel to/from Europe, Israel, Hawaii, or South America is $200. Taxes are not included, so add about $10 for domestic, and plus or minus $60 for international.