How to perform User Research with minimal budget?

I'm business analyst on a project that creates new UI for existing system for public non commercial organization. System has about 9 screens, 3-4 main screens and other secondary screens (less usable and mostly have the same elements as main ones). Mostly it's search for archived documents and display of different types of data, including map view.

Two of those screens were designed with HTML demo and I wrote requirements for development.

Now I need to create home page which is now just bunch of links to other pages. I don't have a budget for any kind of user research. but I still want to create more valuable design. I thought about two options:

  1. Perform an interview with someone how knows the system to learn about possible usage, based on this interview create questionnaire and ask my colleagues for their opinion.
  2. We have workshop for all business analysts in the company, I thought to put all links that I have now at the home page and ask them to sort it (kind of card sorting).

I'm looking for other creative ideas, what can be done in this case? Any help is highly appreciated!