A boxbike (bakfiets) is a kind of cargo bike popularized in the Netherlands. They can be a really useful way to get around — and to move your stuff around – but they are also very expensive to buy (prices are in the thousands).
Here’s an inexpensive boxbike build tutorial by a member of the High Desert Cyclists Club of Antelope Valley, California:
S/he writes “I started this over two weeks ago and spent $50 total [my emphasis]. It took 2 complete bikes and one old long-john project bike to complete it. Many parts were re-purposed. Cantilever brake bosses were used for the steering linkage along with go-kart heim joints.”