The Red Devils are believed to have around 650 million fans worldwide and Old Trafford - which holds 75,000 - sells out every week.
Almost all of those fans - match-going or not - want to get closer to their club by buying some merchandise to show just how much they love their team.
Over the last five years, United have sold an average of three million shirts each year.
But, these days, official shirts aren't the only piece of merchandise you can buy with the club logo on it.
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A quick browse on United’s official club shop and you’ll find branded teddy bears, branded pyjamas and games such as Guess Who and Top Trumps.
In fact, you can buy pretty much anything you want.
But it’s not just the official club store that you can buy United merchandise.
That’s because they’ve had an 11-year partnership with Paul Smith. And the designer brand has just brought out a rather horrific-looking backpack.
Featuring a print of Old Trafford, the designer backpack will set to back a quite ridiculous £440.
The description on Paul Smith’s official website says: "Made from a mix of canvas fabrics with premium leather trims, this backpack features a photographic 'Old Trafford' print with subtle 'Signature Stripe' detailing.
"Complete with a buckle-fastening flap and drawstring closure, this bag comes complete with a quilted mesh back and padded grosgrain straps.”
But guess what, you won’t even be allowed to wear it into Old Trafford.
The bag measures 44cm x 31cm x 16cm, which is larger than what is allowed into the Threatre of Dreams on a matchday.
According to the club’s website, bags larger 20cm x 15cm x 5cm will not be allowed into the stadium.
Paul Smith have also released a set of United cufflinks and a United wallet that will cost £100 and £155 respectively.
We wonder if there’s any United fans out there that will be asking for a Paul Smith backpack, a Paul Smith wallet and a set of Paul Smith cufflinks - three items that will cost you a crazy £695!?News Now - Sport News