Minimum wage is ~12k€/y, so bartenders get basically that. In Spain for people >25yo unemployment is around 40%, which obviously means you get a lot of competition for stable jobs.
Spain in general is very anti-business, especially small/middle business. I had not started freelancing until late in my career because having a paying side job costs you ~$300/month in taxes, regardless of your income this month.
Salaries for senior devs range from 30k to 50k, with very little exceptions.