Was there gst?
You should always assume there will be GST in case you get disappointed because I can tell you it really depends on your luck. I have bought things from other online sites and sometimes I get charged and sometimes I don't even though I bought things from the same site (the items are all more than SGD 400 of course for GST to be levied).
And this has nothing to do with Daiso or any other online seller, assuming they declare the real value. It is the Singapore Customs and I guess it depends on whether the ones on duty are thorough or not.