Basic salaries vary all over the place depending on the industry and a variety of other factors. There are data which can help you calibrate an appropriate base salary. For example, the Massachusetts Software Council puts out an annual Compensation Survey and there are similar publications in other industries. Be sure to establish rational salary ranges given your growth plans. These involve actual payment of benefits by the employer.
Vacation is another cost but is subsumed in the basic salary.
Unless you are hiring traveling salespeople, you need to provide some physical space to house the new employee. Obviously the rent per square foot varies depending on the fanciness and location of the facility. Again this varies but there are some guidelines. Work cubes are typically 8' x 8' in size and private offices range in size. In high tech figure on 225 to 250 square feet per employee when you add in common space.