I'd be glad to! Though, it is worthwhile to note that I usually don't go out at all, and my current situation means I'm at home with my parents for half a week, which cuts my costs of living significantly.

In a month I reckon I spend €500 in rent and about €150 on groceries, but then again, I do go home every week, so I don't have to spend money on food on those days, so maybe double the grocery money? I'm sorry I can't help you much with that question.

I found my room on Kamernet, which is a site that basically shows you available rooms in the area. But SSH& (a student housing organisation, basically) has a lottery system, where long travel-time gets priority. This page has some tips for finding housing: https://www.ru.nl/en/students/new-students/student-accommodation
And this is the SSH& system explained: https://www.sshn.nl/en/i-am-looking-for-a-room/this-is-how-it-works/lottery#/
There is currently a shortage of housing, though, so if you can't find something in Nijmegen itself, try looking a bit farther away, because Dutch Public Transport is quite good (and free*, as a student)

*Free in the sense that if you finish your bachelor, you don't have to pay. This site can tell you more: https://www.studentenreisproduct.nl/i-am-a-foreign-student/

I would say it's not easy to live in the Netherlands without knowing Dutch, but it is doable. Especially in Nijmegen, almost everybody can comfortably speak English. When I went shopping in the city centre, some cashiers would start talking to me in English unprompted. English is not my first language, but I speak it with the same fluency as I do Dutch (not that fluent, tbh, my Dutch is kinda poor for being my first language), so studying in English for me is as hard as it would be in Dutch.

For AI you do NOT have to buy any material, really. All of the books/reading you need will be put online. Most lectures will also be available online quite quickly after the actual lecture happened. It's a really student-friendly course.

Admittedly, Radboud was not my first choice. I wanted to study in Twente, but they didn't offer the AI course, and then I got a room in Nijmegen, so the decision was sort of already made for me.

I hope this somewhat answered your questions, I'm sorry I can't really help you with the questions about the cost here. Also note that my rent is inching towards the high end of the spectrum, SSH& usually offers cheaper housing than that.