Hi,

when I try and run the dryer it makes a loud buzzing noise and nothing happens. No heat, no tumbling. When I hit start button again, it will buzz and nothing happens. One repair guy told me over the phone that it sounds like I need to replace my motor
No model# posted.
Does -sound- like ( no pun intended ) a sour motor
http://www.applianceaid.com/may_motor_dryer.html

Which would run $350 - $400.
Some motors will vary from $125 to $225 for the part.