2014 Freshers: can you buy tickets on the door?

I couldn't afford the wristband and all my friends have it. I decided not to get one because I don't have enough money for taxis and stuff as it is (living at home), and I knew I wouldn't be going to all the nights and events.
I'm planning on going to the Zane Lowe event tonight and the Freshers ball, maybe one other, will I definitely be able to buy tickets on the door?
Don't want to get turned away when all my friends will be getting in.
Thanks!

Also my parents are debating buying me a band, does anyone know if the Guild is open on Sundays so I can pick it up?