Your bike can transport more than just you :-) But remember there are limits - we don't want to see anything like this  on the streets.
Obviously the easiest thing to do is to put stuff in a rucksack, but it's more comfortable to use panniers  on a rear rack . Most adult bike frames are made with attachment points (look for threaded holes above the rear axle and at the top of the seat-stay tubes) or can accept clamp-on solutions.
Many panniers are designed with hook systems to enable them to be easily removed and taken with you. But you can still make good use of those (cheaper ones!) that strap on - simply put everything in a Bag for Life and drop that into the pannier - it's a common sight in The Netherlands.
It's easy to add an attachment for a trailer to your bike and then what you can carry is almost only limited by your imagination.
You can buy ready-made trailers, but we particularly like the Bamboo Trailer  design from the Carry Freedom company (and we like their other products too). So what we need is someone who wants us to make them one. Or perhaps you'd like to make one yourself, using our workshop facilities. Contact us and let's unleash the cargo potential!
Who needs a car now? :-)