My understanding is that there are no huge prizes in this lottery, just a lot of small prizes.
It depends on how much you bet. The big one earns you 20 euros for each euro you bet. In addition there are lots of smaller prices. Every year my dad sends me a “share” on the “tenth” of a number that he plays. I know it is crazy, but that’s the traditional Spanish lottery. BTW, I just checked the results, my dad gets his money back. I won’t see a penny!
Spain has been in dire financial trouble since the Greece issue, and Portugal for awhile too. The understanding was there weren’t enough rich people to even tax heavily, but if they sold tickets I guess that would give them enough money to give out for prizes...I don’t really see how that helps the country.