Computer v. phone data

[Oh_hunnihunni]

I am ditching Spark for Broadband - for a number of reasons - but retaining them for mobile. I rarely use my mobile, once a month call or text if I'm lucky, and never for data. I used to go prepaid, and may do so again, but without a landline I thought I better get grown up and go cell...
Spark's $15 rollover is too much for me. The rollover is mounting monthly and I suspect it will get silly by twelve months, but what is the alternative? There isn't one...