I agree with Fred, high capital business stands a chance, low capital business has been done to death and often needs constant capital input, not really a business.
I did the numbers on Internet Cafe business and realized that it was not viable unless you have large scale operation and lots of GOOD locations.
I know a girl who ran an Internet Cafe business and made enough to buy her own house cash, she now has a house but is also broke, lost the business through being ripped off by people she knew and this is a local girl.
Most of the small scale businesses are like that, labour intensive, require extremely good cash flow management open to collapse from any small event, open to theft and hold up as Penny says or the need to bribe officials all the time. And the margins are rarely high.
Running a bar, pub has some reasonable numbers if you have good location and you can do a reasonable mark-up on the drinks and the usual 100% mark-up on food. Cheapest I was ever able to work out for starting a pub/restaurant was about 6000 pounds and even then the trade would have had to be flowing in less than a month to make it self sustaining.
All of them need you to keep ultra tight control on the day to day operation and cash flow, a normal thing in business but even more so there.
Personally also being technical minded I would go for an online business with a global market that is essentially independent of geolocation and is therefore effectively invisible to the bad guys in the Phils, that way you can still keep a low profile which is pretty much essential for a westerner.
I know of one very successful IT based business over there that was started by a foreigner 10 years ago with very little capital. He had the advantage of being young, having a cast iron contract with a UK company for several years, making the most of his UK and European contacts and being lucky, always an essential in business
Good luck when you do it Fitzy but as everyone says be careful!