Best place to buy firecrackers

There's a huge selection of firecrackers at Wing Tai Chong but I'm not sure about prices. You will find the common "Cerfs" ones, the big red ones which you see for Chinese New Year, the beautiful lights ones and many more.

As you have plenty of time, you can check prices there and on the streets as well. Many "marchand ambulant" will be selling them as well as local shops.