Speaking to BBC Radio Five Live SU chair Nick Towle said: "People are so disillusioned with the massive increases they are being asked to pay, it will just turn more and more fans off,"
"And how is he (Glazer) going to fill an expanded stadium when people are leaving in droves, it's very bad for his business plan."
"The drive for commercialisation is becoming too much for most fans," added Towle. "It's really beginning to create a big problem, and that's just before fans stop buying the products and merchandise, which will also increase in price.
"Our campaign to urge fans to exercise their consumer choice and just not buy the products of the club or the products of the company and the products of the sponsors is going to grow and grow."
However, a spokesman for Glazer's son Joel, recently appointed to the Old Trafford board, told the BBC: "Things are still up in the air. Plans have not been finalised. Nothing has been signed off. These are speculative numbers."
The spokesman also dismissed speculation that Sir Bobby Charlton will be axed from the United board.