How do I invite guests for a Service Design program when the budget is non existent?

The context

When you teach in a public university budgets are limited. Yet to me it's important to bring different voices and personalities so that learners can see the diversity that exists in the same field.

Make it clear it's for a public school

I'm very upfront and say clearly this is for a public school and that it's something pro-bono. I also often explain the idea that instead of inviting one person for the whole semester, I prefer to have many people coming a little time as it offers more diversity to the learners.

Many or little time with no preparation

As usual the problem can be seen as a bug or as a feature. The problem is that there is not budget to invite multiple guests for hours. But this can become a feature. Instead of bringing 2- 3 external guests in a year, you can bring many people for very short sessions.

Inviting someone for 20 minutes, especially when it's for a Q&A that doesn't need any preparation is something that many professionals do pro-bono to help out the next generation of Service Design professionals.

Ask practitioners not keynote speakers

I often tend to not ask people who consider themselves as superstars or who are professional keynote speakers. Instead I tend to invite people who are extremely good at what they do but don't often take the time to be on stage. For these practitioners 20 minutes with learners is a nice break in their day to day. Plus they bring a very "hands-on" perspective that you don't get in books or in Youtube videos.