Retired (2019–present). Lives in General Trias, Cavite.
It really depends on lifestyle and what you consider cheap. We live near General Trias Cavite and do well on under 1000 usd a month. We rent a very decent up and down for only 4500php a month (around 88usd) no aircon but elec fans do OK. Our elec is around 1500php a month (about 30usd) and water is average 250php or less a month. (about 6usd) We don't eat out much. We have gas stove and refrigerator. We also have a Filipino washing machine (common washer and spinner here). We do prepaid Wi-Fi at 1500php every month. We have tile floors and a shower in the tiled bathroom but still a Filipino toilet (flush with a bucket). Our food however can range from 8,000 to 12,000php a month.(150 to250usd) We have a market street right here in the barangay 5 minutes walk. You can buy pretty much any meat or veg you want as well as a lot of other stuff. We also have a pure gold supermarket in walking distance for all the stuff not in the market. We can catch a jeepney or tricycle to all home or to Robinson and SM mall in Dasmariñas for about 60php round trip. Takes about 25 or 30 minutes depending on traffic. There is a BI (Immigration) office at Robinson and that's where I go to do my extensions and such. We are only about 2hr drive to Manila. We don't own a car because I see no need and use public trans. So for me nice no stress living is easily obtained.
Once again depends on your lifestyle and where you want to live. If you choose Manila or Cebu you will pay much more just for basic needs. But further away for metro areas it's a bit less. There are plenty of new construction homes in communities going up everywhere for decent prices if you want to buy. If you eat out a lot you will spend more than what you think even though the prices seem low. It adds up.
I say if you can live a simple life as a couple or even single you can easily do it on 1000usd or less a month but you have to do your homework and set yourself up for success. Having a guaranteed income will also help.