This covers you, your kids and your partner if he/she is not working. If your partner is working, he/she pays like you.
So, imagine you are a family of four, both self employed, the maximum you pay is 656.85€ x 12 x 2 = 15764€/year. This covers 100% of the kids medications, 70 to 100% of the adult medications, 100% of the visit to the doctor and stay in a hospital. You do not have to pay and get reimbursed, you just provide your insurance card and the doctor/hospital will automatically charge your insurance (Krankenkasse).
The system is working a bit differently if you opt-in for a private insurance.
Edit: I cannot reply to the question about the maximum, so, answering as an edit. Yes you have a maximum and the values I gave are at this maximum.
Where I live - there is no limit.
If your _payroll_ is ~1315eur, that means your _income_ is 1000eur, because you've paid (or employer did that for you):
- 15% income tax (~197eur),
- public health insurance 6% (~79eur),
- public retirement fund 3% (~40eur).
- employer pays 31.18% of the _payroll_ to public health insurance (~410eur).
Making the __whole employment price__ - 1726eur, of which 489eur goes to public health insurance. If your __income__ is 10 000eur - everything is tenfold.
I do not know nuances of self employment, but you pay less for the public health insurance. From 1726eur, you'd pay ~234eur for public health insurance and ~181eur income tax - leaving you with ~1311eur.
In most European countries (probably in all of them, but I do have motivation to check) the cost of the health care is paid based on the solidarity principle. This means that the amount that goes for the state level insurer is proportional to the income amount (private insurances for the extra coverage usually work on the fixed amount basis).
Around 500 per person in month is probably not on the very high side considering decent salary levels. The difference is that the health care of the minors is free. This splits the amount in half.