Northamptonshire Police paid the highest unit cost for batons and body armour vests of any force in England and Wales, latest figures have shown.
Data released by the Home Office shows the force spent £11,583 on 117 general patrol body armour vests in July - an individual unit cost of £99.
For the same piece of equipment, the Metropolitan Police bought it for £33.46 per unit and Wiltshire Police purchased the vests for £33.58.
Northamptonshire Police was also found to have paid out the most money for batons, buying 250 in January 2014 at a cost of £82.91 each.
The figures show the vast majority of forces across England and Wales bought batons for less than £50 each, with South wales Police buying 200 for a unit price of £22.99.
The Government wants forces to adopt a collaborative approach to procurement to take advantage of potential savings.
Mike Penning, Minister for Policing, Crime, Criminal Justice & Victims, said: “For too long the police have approached the market in a fragmented way, buying equipment in small amounts and to varying specifications.
“Since 2010, police forces have increasingly worked together to buy goods and services and reaped over £200 million in savings by doing so.
“But there remains more to do. It makes no sense for forces to buy separately when money can be saved if they act together. That is why I have published key police procurement information on the prices that forces currently pay for the most common items of uniforms and equipment.
“This will help the public and Police and Crime Commissioners hold Chief Constables to account for how they spend taxpayers’ money and, crucially, reveal potential opportunities for further savings.”
A spokesman for Northamptonshire Police said it was looking at collaborating with other forces to reduce the cost of buying equipment.
The spokesman said: “In some of these cases, pieces of equipment bought by other forces are cheaper alternatives to the ones we provide our officers.
“We are however actively working on reducing procurement costs and have been for a while now
“As part of our collaboration work with forces across the region, we are also looking at procurement costs generally, which will provide an opportunity to look at more effective ways of buying kit in the future.”