Amy Wilson, who gave an address in the Borders, was fined £300 with a £20 Victim Surcharge, as well as being told to pay the store £75 in compensation.
The 34-year-old – who receives more than £1200 a month in benefits – was also ordered not to enter the premises for the next three years.
Co-accused Kendra Morris, 33, from Galashiels, had sentence deferred until next month for the production of background reports.