We recommend a table saw as well, although you can build the cart without one. But don't worry if you don't have a table saw; most suppliers will cut the wood for you for a small charge.
Wheelbarrows are great for hauling stuff around the yard, but they have their limits, especially if youre working on a hill, ...
While they specialize in making go-karts and minibikes ... for so long that the wooden platforms had started to peel and rot. Then they headed back to the shop and got to building.