Scratch

If you buy you GBA games from ebay or used game stores. Check if ts fake by..  just use these steps to see
Ways to Tell:
1. Label isn't shiny
2. Poorly placed label
3. Cartridge isn't coloured (for all Pokemon games)
4. Nintendo logo not visible
5. Diffrent cartridge label
6. Poor Build Quality
7. Batteries on no-battery. games, Like poke mon firered.
8. Actual game is different when played.
9. Doesn't fit correct in GBA.
10. No nin tendo logo on the cartridge connectors.
Heres a video quide

http://www.scratch.mit.edu/ext/youtube/?v=FkgJFxzf_PU

Thanks to some guy on youtube for the 10 steps.