Build an app for garbage collection reminder

Specification for garbage reminder app. Android and Apple I want to have this app as a free service to the residents of my area in Tasmania, Australia so I don’t want to spend a lot. Garbage is collected fortnightly. Collection day is determined by suburb. For example Lanena, my suburb is Fridays on week B. There will be a dropdown menu to select suburb. User sets up how the reminder will be sent – sound, picture and when and how many repeats. App runs in background and alerts similar to calendar alerts. When the reminder comes through there will be a message (different every fortnight) such as “collections over holidays will be the same as normal” “don’t forget to take the lids off glass jars before putting them in the recylcling” Users will be able to open app and find out when is next collection. Future use might be another collection day. At the moment both the recycling bin and garbage bin are collected on the same day. Another bin ( green waste) might be added and that could be on another day – need to allow for that in design of software. ISSUES: Cost, guarantee? Does s/w belong to me – if I want future improvements can I use another developer? What would be the hourly cost for future changes. How are the weekly messages uploaded? What is the annual cost to Apple & Google