I was thinking 5 a month, 25 6 months, 45 a year, but considering Netflix base price is not much more than 5 a month and their operating costs will be significantly higher than mine per user I am wondering if it is too much (but also worrying too little a price will make people not willing to pull their wallet out)
While 5 a month doesn't sound like much, I don't think families want to subscribe to a whole bunch of such cheap services. You have this messy intersection of willingness to pay, value rendered, cost of small vs big scale.
I wonder if bundling is the answer, either with your own group of apps, or join forces with other family software companies. I wonder if in the future there could be reseller-aggregators for groups of the most popular family apps, wrapped into one subscription package.
If it’s to get rich, take somebody else’s money (if you can), make the app free, grow it huge, and then sell it. If pocket money, say $10-20/month and weed out nearly everybody who’s price-sensitive. If sustainable primary income is your goal, $5 a month tops. The last option is least likely to succeed IMO.
You should also look into pivoting and serving profitable small businesses (if there is a business use-case for your app). Much easier to convince them to spend $10 a month than a family to spend $5.
Regardless, this is going to take a lot more marketing and community building than you think to make anything more than pocket change.