Hi there,
I would begin by contacting the university itself and request access to one of their rooms or spaces such as their sports hall for a certain amount of time. That way, hopefully, you don't have to pay for a venue to host your event since the university itself is offering a room or open space for you.
I would recommend hosting the event from 10am till about 4pm, ideally on a Saturday, since majority of the train and bus services are frequent, in case anyone uses public transport, compared to on a Sunday, furthermore, because majority of the attendees are most likely to be busy during the weekdays with either school or work.
In terms of food and drinks, I would ask for help from your friends and perhaps share the cost equally. Maybe stick to one set or two sets of foods and drinks. (I was working on a graduation day, and the university catering team only gave the graduates and the guests strawberries with cream and prosecco for free, that's literally it. The university events team had invited other food and drink companies however they would charge attendees if they wanted to eat or drink something else).
Or if you wanted to, you could bake at home, but ensure that whatever you bake is suitable for vegetarians and non-vegetarians (and consider, of course, allergies).
Or another option is making your event online, lasting around 2 hours or so. You won't be spending a single penny. And anyone will definitely join since it's online and they will be in the comfort of their home rather than having to travel so many hours to the event in-person.
I hope this helps.
Best wishes,
Narusha
Coventry University Student Ambassador