Mischa Barton is about to get a plea deal for her DUI case, stemming from her December 27 arrest in West Hollywood. The 22-year-old will plead no contest to the misdemeanor driving-under-the-influence charge, an insider tells E! News. If the deal goes through, Mischa will avoid jail time, the marijuana possession charge will be dismissed and another charge for driving with an invalid license will be reduced to an infraction. According to the insider, Mischa will probably get three years of unsupervised probation, attend a three-month alcohol education program and pay a fine. "That has always been the plan, but we don't know exactly how the deal will go down," says the insider. Prosecutors are expected to sign off on the deal, which is considered a common one for first-time offenders like Mischa.