The city council revealed it would put £113,450 into new books for its 16 libraries this year - a fall of £100,000 on the year before.
Other Black Country and Staffordshire councils are continuing to spend vastly more - with one neighbouring borough even increasing its budget.
Sandwell will put £400,000 into new books alone this year, plus a further £80,000 for other materials such as DVDs, CDs, audiobooks, magazines and newspapers.
It was an increase of £6,000 on the previous year to account for inflation.
Staffordshire County Council will also keep its £625,000 new book budget the same.
And Walsall Council said its spend on library stocks would stay at £580,000.
The cuts to Wolverhampton's library books budget comes before a proposed £500,000 reduction to the overall budget for 16 libraries - currently £1.7 million - as part of £134m worth of cuts over five years.
The move is almost certain to result in job cuts and shorter opening hours - on top of reductions already made to opening and a plea for help from volunteers.
The figures for Wolverhampton, which do not include its spending on CDs, DVDs and periodicals, emerged after it was revealed Birmingham City Council was reviewing new library book requests on a case by case basis and some staff were even appealing for donations from the public.
Wolverhampton council's libraries boss Councillor Elias Mattu said the authority had to make difficult decisions.
Councillor Mattu said: "The budget reductions were something we were not happy with.
"A lot has already been taken from the libraries service.
"The more that savings targets are increased and the more the government cuts from our funding, the more difficult it becomes.
"We currently have a proposal to take a further £500,000 out of the library service.
"It is just a proposal at this stage and I want to make sure we are not in the position of losing libraries altogether.
Asked about the cuts for new book buying he said: "We still believe in the libraries service. It's an important part of life in the city.
"But libraries are not just about books. They are used by people for a range of services including accessing the computers.
"This is a difficult area and I will be fighting to keep libraries open and protect the service for the future."
Pru Coleman, who was part of the Save Wolverhampton Libraries campaign that gathered thousands of signatures on petitions against cuts already made, said: "It sadly shows what we predicted is coming true. We were accused of scaremongering but we could see the writing on the wall."