Being a Dutch cheapskate I set up our builder and GIT server mostly with free tools
(with the exception of Dotfuscator which is paid)
All on Windows and we are building locally mostly .NET projects.
The GIT server is
Gitea[
^]
The builder is
TeamCity[
^]
Database for Gitea and TeamCity:
PostgreSQL[
^]
As TeamCity has a learning curve (as most CI tools) you could also consider starting with Gitea only and see if that meets your demands.