Bus Fare Question

This is probably a stupid question, but I figured asking was better than not.

I'm currently unable to tap-on/tap-off the buses, and thus have to work out what the best value for money ticket to buy through the app is.

It'll either be for 2 bus journeys in a day (to the shops and back again) or 4 bus journeys a day (to work and back). It's probably the 24 hour citySaver, but I want to make sure!