Thanks to @ItsYaBoiSlayer developer who makes Cydia purchases is possible in iOS 11 Electra jailbreak.

This is a MobileSubstrate tweak that hooks the web requests from Cydia to spoof your device. It is completely safe and does not modify system files. He made a tweak instead after tinkering with the tutorial earlier today.

Add this http://randompacks.yourepo.com/ on your Cydia repo.

Here is the video for how to: