I am very allergic to cock roaches. Just a whiff of it can bring me down with an asthma attack. Our first home had a lot of roaches when we moved in and we tried to get rid of them by spraying every night. Problem was, I was allergic to the spray as well (even water based ones).
I discovered Baygon's 24-hour tablet roach killer at SM Hypermarket. It's a bit pricey at PhP159, but I got one box in the hopes of getting rid of the roaches at home and to save me the pain from having asthma attacks.
I'm glad I made the investment since all the roaches were gone in two weeks and we were roach free for a whole quarter. That's just about PhP50+ per month. We replaced the tablets a week before it would reach 90 days.
Based on the product description what it does is attract roaches to the tablet. Once inside the poison sticks on their body and they bring this back to their colony, thereby killing all roaches in the vicinity of your home. And it works! Aside from homes I strongly suggest public places like offices, restos and stores to place this tablet around because it would definitely get rid of those roaches.