I used to joke that businesses in Singapore have a captive audience since the country is an island. The meaning was that you should be able to do a thriving business no matter what you offer since there would not be a lot of competition. However, there actually is a lot of competition to grab as much of the market share of Singapore consumers that you can, and one way advertising is done is through door to door flyer distribution. We don't see a lot of that in the US, but it is popular in other places.
In Singapore you can pay a company to print and hand out your flyers. They will put them on cars, hand them out in busy places or canvas neighborhoods doing door to door flyer distribution. If you develop a slick flyer that makes a great offer to grab consumer attentions for your business, you can acquire a lot of new customers in a short amount of time with just handing out flyers. The companies that offer this service can hand out thousands of flyers for a low price making it a worthwhile marketing campaign.
Back here the flyers would probably be inserted in newspapers or in advertisements that are typically mailed to people in the region you want to market to. In Singapore you can hire people to hand out the flyers to get them into the hands of individual customers in the area you want to target. Within hours thousands of people know about your latest marketing campaign for your business, and it can be done for a very low cost for the amount of people that get reached. I'm not sure that would work over here. You would probably have problems with getting the flyers out into the hands of the people. For example, they will put them on parked cars. Here, that is illegal in a lot of places.