Over the years, some big-money signings have flopped and ended up leaving for nothing, while others have gone on to become club legends and more than justified their costly price.
With spending in football being reigned in among ongoing financial uncertainty caused by Covid-19, we aren't expecting to see a huge amount of record deals landed this summer, but there could yet be some surprises ahead of the 2021/22 campaign kicking off in August.
In the meantime, for a bit of pre-season fun, we've taken a look at every League One club's record signing fee, as well as the side they turn out for now.
Here's a look at how Sunderland' s record signing fee shapes up against every other club they'll be facing in League One this season:
1. 24th - AFC Wimbledon
Record signing: Byron Harrison. Estimated transfer fee: £25k+ (from Stevenage in 2012). Current club: Now 34, he was recently released by National League side Altrincham. Harrison helped Barrow AFC win the National League in 2020. Photo: Oli Scarff
2. 23rd - Cheltenham Town
Record signing: Jermaine McGlashan. Estimated transfer fee: £50k (from Aldershot Town in 2012). Current club: He made over 100 appearances for Cheltenham, before joining Gillingham in 2014. He's now the joint-manager of Ashford Town U18s. Photo: Michael Steele
3. 22nd - Lincoln City
Record signing: Tony Battersby. Estimated transfer fee: £75k (from Bury in 1998). Current club: The ultimate journeyman, Battersby has played for no less than 29 clubs. He's still on the books at Boston Town. Photo: Dan Smith
4. 21st - Accrington Stanley
Record signing: Ian Craney. Estimated transfer fee: £114k (from Swansea City in 2008). Current club: Craney spent a total of three spells with the club, winning the Conference National in his first spell. He retired in 2015. Photo: Pete Norton