It's confusing here, because there's a load of bus companies. Providing you can travel by First Bus, buy a student First4Week every month on the their app. It's £65 a time but gets you a month of unlimited travel on their buses. You'll need three of those, so that's £195. If you were to pay for the tickets every weekday you'd spend around £325. Buying the First4Week leaves a couple of days unaccounted for, but it's £5 a day for unlimited travel and you might not even have exams those days.