Jodie Fiona King, 39, was charged with two counts of theft after charity boxes were stolen from Easytan salon in Western Road, Bexhill, at 6.20pm on Tuesday, January 14.
On Thursday (January 16), King appeared at Hastings Magistrates Court where she pleaded guilty to the two charges against her, a spokesman for the Crown Prosecution Service (CPS) confirmed.
The spokesman said she was fined £80 on each offence, ordered to pay £85 costs and a £32 victim surcharge.
One of the charity boxes was intended to raise money for seven-year-old Denny Nassy, who has acute lymphoblastic leukaemia, so he can have pioneering treatment abroad.
His family has recently appealed for a large donor to step forward to help the youngester.
His aunt, Michele Laurens, launched a fundraising page online four months ago, with the aim of raising £500,000.
So far, more than £175,000 has been raised through numerous donations from well-wishers and charity events.