Lisa Williams told officers her car, which they suspected had been used in an aggravated burglary, had been parked outside her house when she gave a statement, on March 18.
Prosecutor Robert Carr said: “Automatic number plate recognition saw her car in Mansfield on the night in question and this contradicted her statement.
“She admitted lying in her statement and said she had driven to Shirebrook to pick up a friend’s brother and they then collected drugs in Mansfield.”
Williams, 36, of Vickers Street, Warsop, admitted obstructing a police officer when she appeared at Mansfield Magistrates Court, on Thursday.
The court heard she had previous convictions for dishonesty and failing to comply with a community order.
Rebecca Williams, mitigating, said: “She gave her friend’s brother a lift, not realising what he was going to do. He bought drugs and she didn’t know he was going to do this.”
She said the mum of three, with children aged seven, ten and 14, was concerned what would happen to the man if she told the truth.
“It didn’t impact on the investigation,” she added.
Williams was fined £80, with a £30 victim surcharge and £85 costs.