As a middle class kid in Spain during the early 80s we didn't have Legos either. Spain was barely starting to enter the international market after the Franco era.

But we had Tente which was amazing. I spent hours and hours building stuff (vehicles, space bases, robots, etc) and making up stories about these things.

See some images here: https://www.google.com/search?q=tente+toy&tbm=isch

Edit:

The sets were fun for like 1 hour, but in the end all the pieces ended up in a huge bucket (actually a big wooden drawer hidden under my bed) and the real fun began.