Gimp and Open Office are completely free if you downlod them from the open source organizations that created them. No sneaky search bars, antivirus that you don't need, adware, etc.
These are open source programs that operate off donations of mo ey and programming expertise, similar to Wikipedia.
However, there are a number of other sites that offer their own free download distributions of the same software. These unofficial sites often DO have search bars, adware, and other junk snuck into the install.
So, use the links from the open source orgs for open sourced freeware. For other software, be careful to read before you click.
NIH image and Jimage were developed using US tax dollars. They are also completely free from the NIH site. There are probably "enterprising" persons offering unofficial free downloads of the same software - with adware and malware added.