It depends on how much experience you have and what area you are working in. Heavy machinery diesel mechanics can make over 100,000 a year. It depends on your area, and power generation diesel mechanics easily make a lot more than that.
How much money an herbalist earns can vary greatly. Those who work in a health food store an earn $20,000 per year. Those who work in sales can earn up to $75,000 per year, and those who are self employed can earn over $100,000 per year.