The Sweet, in their 1970s glam rock pomp, rode high in the charts
Saturday's show was the idea of the band's guitarist Andy Scott, who hails from the town and supports the team.
Wrexham Supporters' Trust, which is aiming to let fans buy a share in the club, hope to have raised £8,000.
The Sweet were one of the UK's biggest and glitziest chart groups in the early 1970s, with hits including Ballroom Blitz, Hellraiser and Blockbuster.
The League Two club was saved by an 11th-hour deal in August after having been financially stricken for 18 months.
The club was bought by a consortium headed by local businessman Neville Dickens after going into administration in 2004 with debts of about £4m.
Three weeks ago Wrexham AM John Marek loaned a large sum - thought to be about £500,000 - to the club.
Their latest unlikely benefactors are a band who had 10 top 10 records, including five that reached number two.
Scott, 57, said: "My brother Geoff and I have been lifelong fans of Wrexham.
"A football club is the lifeblood of a town or city and I just thought how I had to help Wrexham. In the end it was an easy decision for me.
"But I don't want anyone to think I'm an Elton John-style benefactor. I've enjoyed success in my life but I don't have that sort of pocket money."
Mr Scott, whose brother Geoff is a member of the Wrexham Supporters' Trust, confessed that the last time he was at the venue for Saturday's gig - William Aston Hall - he was in the scouts.
The supporters' trust sold more than 800 tickets for the show and said it was a "great night".
"Andy told us afterwards it was one of the best nights he'd experienced in a long time," said Peter Jones, of the trust.
Fellow supporters' trust member Dave McGuire said the trust had raised about £200,000 and was only a few thousand short of its £250,000 target.
Only two of the original members of The Sweet - Andy Scott and Steve Priest - are still alive.
Lead singer Brian Connolly died of liver failure in 1997, and drummer Mick Tucker died of leukaemia five years later.