Jason Alexander, 39, used a company credit card to buy almost £91,000 of iPads, phones and computers.
Alexander, of Griffithstown, Torfaen, admitted fraud and was jailed for two years in January.
But at Cardiff Crown Court on Thursday, a judge ordered him to pay back £115,000 to his ex-employers.
"It seems you were doing it as some kind of philanthropic act," Judge Stephen Hopkins QC said.
"In some cases spending £5,000 on items and then selling the items to employees for as little as £180 on the philanthropic basis they will not have been able to buy the items themselves."
He ordered Alexander to pay his ex-employers £115,867 within six months or face an additional 18 months in jail.
"You had an enormous impact on a large number of perfectly innocent people," the judge added.
"Those to whom you sold goods to now feel stupid and stressed.
"The impact upon your colleagues has been awful. You have stolen from the company and there was a dip in morale for a period.
"This was a gross and serious breach of trust over a substantial period of years."
Alexander had control of spending at car parts company, Northern Automotive Systems in Gilwern, near Abergavenny, Monmouthshire.
He made 287 purchases on internet sites such as Amazon, eBay and Argos.
The court heard the company's usual monthly credit card bill was in the hundreds, but when Alexander became purchasing manager the bill "increased to nearly £10,000 per month".
But his scheme was discovered when suspicious company managers asked employees if they had bought cut-priced electrical goods.
The conman deleted emails as well as falsifying invoices, receipts and card statements to cover his trail.
Alexander, who had worked at the company for 14 years, bought petrol for his white Land Rover, red Mini and his partner's Ford Fiesta.

City thought a £40m deal had been agreed for the Argentine striker after he told the Premier League outfit he wanted to return to South America.
But Corinthians said there was not enough time to sign the the 27-year-old before the Brazilian transfer window closes at 0400 BST on Thursday.
Corinthians still want Tevez and hinted an agreement can be reached in January.
It had appeared that the former West Ham forward had got his wish for a transfer but then in a statement, Corinthians said: "The board of Sporting Club Corinthians hereby officially announce the impossibility of hiring the Argentine striker Carlos Tevez.
"While acknowledging the efforts of Manchester City and all involved in the negotiation, more time is needed for the transfer to be achieved, given that the window to sign players from abroad closes on Wednesday, 20 July [Brazilian time].
"We are aware of the dream our fans had of having this player at Corinthians again and we look forward to him being with us in the near future."
That would indicate that Corinthians may look to revive the deal in the January transfer window, although that would not be the preferred option of Tevez or his current club.
Tevez, who had a spell at Corinthians from 2005 to 2006, originally asked City for a transfer in December and has since reiterated that desire to leave so he can be closer to his family in Argentina.
However, there are few clubs who can match the asking price of about £40m.
Corinthians' move for Tevez - which emerged on Monday - was believed to be funded by a new television deal for Brazilian clubs.
But the Sao Paulo side's response to City's demand for a proper payment schedule on Tuesday was perhaps a sign the transfer would not have gone smoothly.
The breakdown of Tevez's transfer to Corinthians also leaves City manager Roberto Mancini's proposed move for Atletico Madrid striker Sergio Aguero in doubt.
Tevez, who is contracted to City until 2014, has been a key player for the club since arriving from neighbours Manchester United in 2009.
He helped Mancini's side to FA Cup success and Champions League qualification in the 2010/2011 campaign. He has scored 43 Premier League goals in his two seasons at City - the highest total of any player in the top division.

Galloway also missed the end of last season, having ruptured the Achilles tendon in his other leg.
The 31-year-old's latest injury will also rule him out of Scotland's squad for the World Cup starting in October.
Galloway has made 43 appearances for Leeds since joining from NRL side Wests Tigers ahead of last season.
A man who used money defrauded from his employers to buy then sell computers to colleagues at knock-down prices must hand back more than £100,000.
[NEXT_CONCEPT]
Carlos Tevez's move from Manchester City to Corinthians has fallen through because the Brazilian club pulled out.
[NEXT_CONCEPT]
Leeds Rhinos prop Keith Galloway will miss the rest of the season after rupturing his Achilles tendon in the Super League win over Hull FC.