1. Stop complaining about the price of cement. Start Digging.
Wise civilizations have always built homes with what they have, not with what they have to obtain with difficulty. Today's Nigeria is not a wise civilization I suppose, or we would use laterite bricks more.
What is laterite? The answer may be beneath your feet at the construction site.
Meet the experts, read their books and study their works, for example The Architecture of Renowned Master Demas Nwoko
3. Lower your running costs too
Fire NEPA/PHCN/xxDC , throw away the noisy generator (or give it to your enemy lol) and be your own solar power provider. Also remember to build in time-tested natural ventilation and passive cooling systems from day 1, from the first drawing your architect makes.