For the US, and from my understanding, this is some sort of gray area. Law states you can legally import a 90 day supply of most medicines. I believe that only applies to medicine for which you have a prescription.
Buying Script only meds online without a Script is illegal. However, they are easier to obtain than scheduled medicines online. My friend, Generally though, it's a bad idea. The government is really cracking down on online drugs, and even the unscheduled drugs are becoming fake, rare, or just being sold by companies who take your money and run.