Hello @Alex,
all CPE or IELTS courses are cost-intensive. Most adult education centres offer very good C1 or C2 courses for an affordable amount - so just take a **** at the homepage of your local "Volkshochschule".
If such courses are out of question for you due to the costs, you could try to learn via Internet.
Splendid speaking and Flo-Joe are fantastic sites and the basic program is free. There are also some very good apps you can download, such as BBC Learning English, Word UP, IELTS Word Power, Elsa Speak or English Idioms. You could also benefit from the TED talks, as there are transcripts on the page. The Khan Academy offers free material for all linguistic skills.
Don't hesitate to come back to us if you have further questions.
I hope my answers were helpful and I would be very happy if you would contact me again with further questions. I'm a consultant with mbeon and I‘ll be glad to help you over a longer period of time. Mbeon is an online advice for migrants via the mbeon app, which you can install on your smartphone for free. Download it from App Store or Google Play Store. You can find me in the mbeon app and get confidential individual advice in a secure virtual space without other people reading our conversation. Further information: ***.mbeon.de.
Best regards, mbeon-Christine