Technically they could completely ass rape you for ordering even a single bud of weed. You could be charged for money laundering, being a participant in a continuing criminal enterprise, trafficking drugs over state lines or importing drugs, conspiracy, obstruction of justice (a charge they like to throw at people who use encryption and anonymizers to avoid investigative efforts) and probably a dozen other charges, locked up and have the key thrown away. That said they are very unlikely to actually do this to people who are ordering personal use amounts, but legally nothing is preventing them from doing it, and who knows if the jury will nullify considering technically you will have broken all of those laws. It is far more likely that you will be charged by the state (not feds) with something close to equal to what you would be if you were found with those drugs after being pulled over, which could be anything from in or out patient drug rehab to a few months in jail or years in prison (which will be mostly spent on parole) for personal use amounts, depending on where exactly you live. People who are ordering larger than clearly personal use amounts (for example ordering sheets of acid or ounces of MDMA) are more likely to be charged with more serious offenses like drug trafficking and will likely be sentenced to several years in prison (with most on parole) instead of jail or rehab. People who are shipping product will almost certainly spend at least a few years in federal prison (which has no parole), and the significant vendors and organizers will probably be hit with all of the nasty charges from above and die in prison. They will likely charge you with slightly more serious crimes than they think they stand a strong chance of convicting you on, because they want you to plea guilty to lesser charges and they know you will not risk the chance that a jury will convict you on trumped up charges. So even if they charge you with drug trafficking for getting a bud in the mail, they will probably immediately offer you a plea bargain where you are charged with simple possession if you agree to plea guilty. The plea bargain they offer you will largely depend on how much money you have spent on a lawyer.