Today is last day of GOSF, if you all have not purchased, you still have one more day to go, include Starhub : gosf.sg
I also just use this site shopback recently that surprisingly works well as it is able to offer cash back on purchasing online through most of the sites, e.g. Groupon gives you 4%. The way it works is simple, just go to this site: https://www.shopback.sg/r/3PQFRY, register, and then whenever you want to make a purchase, just search for the site, e.g. groupon, access it from there, and just purchase as per normal.