Nadia Oates used the vouchers and expensive gifts stolen from packages sent to loved ones to brag about her apparent wealth.
Russian Oates, who moved to the Britain 15 years ago, sent some of the stolen goods back to family members in her home country.
The 58-year-old stood with a translator in the dock as she admitted to one count of opening mail as a Royal Mail employee and two counts of theft.
A search of her home found 19 unused gift vouchers, 16 books of first class stamps and a number of receipts from high street retailers revealing accounts of luxury gifts she had bought over the six months period.
The court heard how the Russian national started her six-month spree when a gift voucher fell out of a damaged letter.
After realising she could spend them without being traced, Oates trawled through cards and gifts to steal them.
Thomas Edwards, prosecuting, said: “What was discovered is a result of a tip-off after a report that opened packets of mail had been found in sanitary bins in the ladies toilet. Some of these packages were found to have her fingerprints on them.
“Vouchers for shops such as Boots, TK Maxx and John Lewis were found as well as receipts for £3,389.36 of goods that were paid for entirely by the use of gift vouchers.”
The selfish sorter was caught when a customer complained about a birthday card they had received without a £40 Love 2 Shop gift voucher.
Several open packages were discovered in bins in the ladies’ toilets next to where Oates worked.
Fingerprints on the packages matched the mother-of-four, from Aspect Court, in Slough.
Nyll Thompson, defending, said: “She deeply regrets what she did.
“When exploring with her why, at the age of 58, she succumbed to the temptation to steal in this way, it seems that she felt an expectation from her family back in Russia that after living in the UK for a number of years she would have a lot of money.
“She wanted to be able to show them this and found this was a way to send back presents.”
Judge Alexia Durran, sentencing at Reading Crown Court, said: “You were stealing to provide gifts and not necessities and it was greed, or an inability to face up to your personal situation with your family that led you to commit these crimes.
“You caused alarm, disappointment and distress to members of the public. You caused damage to the Royal Mail and members of the public. You accept responsibility for your actions but this was only as a consequence of being found out.
“It has undoubtedly caused your 21-year-old daughter distress at finding out her mother has fallen into temptation and fallen into greed borne out of a desire to satisfy your family’s expectations.”
Oates was sentenced to a total of eight months in prison.