You will need a PlayStation 1 emulator to play SaGa Frontier. You can download emulators from my emulators page. If you need assistance with any of the emulators offered on my site, check out my emulation help subsite: Video Game Emulation for Newbies.
Due to the release of SaGa Frontier Remastered, I can't host the PS1 game for download here. Rather, try the links below for collections at Internet Archive. Click here if you need directions with that. If Internet Archive doesn't work out for you, I have more options in my links.