The hourly wage for domestic helpers (incl. social security contributions) in Spain is between € 8.50 and € 14, with regional differences.
The domestic helpers on Doméstico24 determine their hourly wage themselves based on their experience and qualifications — and they state this in their profile. However, the wage is a matter of negotiation between you and your domestic help.
You can also find more information on wages here: How much does a domestic helper cost?