Melissa Etheridge Avoids Jail with Plea Deal in Drug Bust

Melissa Etheridge can keep on smiling' -- she made a plea deal in her marijuana possession case that keeps her out of jail.

Burke County State attorney Amber Fiesel tells TMZ ... Melissa pleaded guilty to possession of a controlled substance, a Class B misdemeanor. She'll pay $1,000 in fines and fees and get 6 months of unsupervised probation. If she keeps her nose clean during that time, the case will be tossed.

Prosecutors wanted Melissa to submit to drug testing, but the judge shut that down after hearing Melissa has a medical marijuana card in Cali to treat her cancer-related pain.

As we reported ... Melissa's tour bus was stopped near the U.S.-Canada border in North Dakota back in August, and a K-9 detected her marijuana oil.