If you consider studying in Portugal, Austria, Mauritius, Czech Republic, or Italy without family you should budget 5 – 7 million naira.
If your budget is about 7-10 million naira, you should consider Portugal, Luxembourg, Austria, Mauritius, the Czech Republic, and Italy with dependents but maybe not immediately.
You can go to Malta and Finland if your budget is 10-15 million naira. Malta has the easiest Admission process; you can move in within three months.
If your budget is 20-30 million naira, you can add the United Kingdom to the above-listed countries.
If your budget is 30-40 million naira, you can add Canada, Australia, and the United States to the above-listed countries.
Please note that you can get a scholarship if your profile is competitive.