It depends on lot of things,  but most importantly

1. Your budget

2. The structure of medical education

3. Living standard of the particular country

Here is your list. 

1. Georgia

2. Ukraine

3. Philippines

4. UK

5. Australia

6. Germany

7. Canada 

8. USA

First three are the cheapest. 

Hey santhu! The two countries best for pursuing MBBS abroad are China and phillipines. China itself has 45 medical institutes approved by MCI. Ningbo university and jiangsu university in china are best ones for MBBS. Angels university foundation is best in phillipines . Well you can also pursue MBBS from national medical college and nepal medical college from nepal ,odessa national university in ukraine and mordovia state university of Russia.