The standard smoke detector costing about 300 pesos on your local hardware is the ionization type smoke detector. It is the cheapest type of home smoke detector utilizing the radioactive Americium-241 to detect the presence of smoke. Americium emits alpha particles which makes the air inside the smoke detector unit partially conductive.  Smoke particles absorb alpha particles and increases the
resistance of the air inside the smoke detector. The rise in the
electrical resistance of the air is detected by the ASIC and then it triggers a piezoelectric horn.

Ionization type smoke detectors are cheap and accurate but you may be concerned about AM-241 which actually emits
radioactive particles inside your home. FDA says that the
alpha particles emitted by the standard smoke detector is lesser than the amount you are going to get from sun exposure.

On the other hand, photoelectric
smoke detectors use an LED and a photodetector combination. The photodetector senses the presense of light that is reflected by the smoke particles and triggers an alarm unit. Early photoelectric smoke detectors are prone to false
alarms because of dust build up. Newer ASICs from TI, Allegro and other manufacturers  resulted in a more accurate and cheaper photoelectric smoke detectors.

It is important to note that ionization and photelectric detectors detect different types of smoke. Ionization type is more sensitive on smoke particles with small sizes that usually comes from high temperature fires while the photoelectric type is sensitive to large sized smoke particles coming from slow, smouldering fires.