When you have been Autonomo, closed up shop, never paid for the extra insurance for ´cese de actividad´, so no rights to claim ´paro´….
When you´ve exhausted all state benefits, paro, subsidio, ayuda familiar, Renta Activa de Inserción, not eligible for pension, either contributivo or non contributivo…
Then you need to turn to Servicios Sociales at your Town Hall to enquire after the possibilities to receive social benefits. Known under many names, Salario Social, Renta Social, Renta Minima, Ingreso de Solidaridad, etc.
If local Servicios Sociales does not have any program available, you need to go to Servicios Sociales of your Autonomous Region. Either in person, or inform yourself first on the web.
More info and Links to the relevant webpages of the Autonomous Regions.
Update January 2018. Andalucia e.g. has approved ´Renta Minima de Inserción´ available for those with income under 415 euros/month. Between 25 and 64 years old. Or between 18 and 24 but with dependent minor or disabled person. You need to have been on the padrón for at least a year, registered as unemployed and looking for work and agree to follow a personalised ´plan de inclusión sociolaboral´ to improve your chances to obtain employment. More details with the social worker in your town. Servicios Sociales.