According to square, a single transaction uses at most 50kb (with a signature). so it would depend on your sales. Assuming you are a somewhat busy shop and you run 800 transactions in a month, it would add just over 39MB per month.
Source: https://squareup.com/help/en-us/article/4963-data-plans-and-sms-policy
Does going on safari use data
When you use the Internet.
only what you initially put on you profile. Facebook can not secretly spy on you true your iPhone or go true personal data that is not on you profile. an exception to this rule is what you search on Facebook it self.
No
No
30mb per hour, upto 60 if you keep changing
So my question is: if I use my iPhone and go on a website, will that website data cookies save on both my iPhone and iPad since they're the same account?
No but it is cheaper because i was a pay as you go customer and because I was not on an Iphone tariff i was charged £1 per day for data, so if you can get iphone tariff for like £15 that is like 15 days worth of data but you get it for a month
Yes, it is free. Where you use data is when you stream movies and videos.
It's part of your data plan.
Not really no.
It comes as part of your iPhone's data plan unless you only use the WiFi to access the Internet. The data plans start at $30 USD.