Pierre-Emerick Aubameyang’s departure to FC Barcelona is set to save Arsenal money, with various reports detailing their understanding of how much.

In the end, Pierre-Emerick Aubameyang’s move to Barcelona was officially a free transfer.
He cancelled his contract with Arsenal before signing a new one with the Catalan club, meaning the Gunners didn’t receive a fee for him.
Instead, the potential financial benefits to Arsenal come in terms of saved salary and bonuses.
Aubameyang was reportedly on wages of £350,000-a-week with Arsenal, and he had 18 months left on his contract.
Tally that up, and it’s around £27m. The Athletic back that £27m figure up.
However, Goal report that Aubameyang’s departure will actually save closer to £20m in wages.
The £7m difference between these two figures might be explained by a report from The Times. They write that Arsenal paid Aubameyang a lump sum to terminate his contract, believed to be almost £7m.
The Guardian report that Aubameyang waived his salary, and Guardian reporter Sid Lowe told the Daily Cannon that the player had also let Arsenal off the loyalty payment owed at the end of his contract.

Assuming all of the above information is correct, Arsenal’s total savings will come to more than £20m.
That’s £27m in wages plus the loyalty bonus, less the reported £7m pay-off.
Now they need to put that saved £20m towards a new striker in the summer.