navigation renewal

Hello all this is my first time on any forum so apologies if I dont get it right.
Is there any way to update the maps in my A3 TDI on a 17 plate, without having to pay my local Audi main dealer £250?
I bought a TomTom sat nav a couple of years ago and that came with lifetime map updates. Google maps on my phone is always updating itself. So why do I have to pay Audi £250 for the privildge?
I love my A3 and this is my second A3.