Your asking for quality, but naming places that are anything but.

Ikea furniture is very easy to assemble, inexpensive, looks ok, and you will get a few years out of it provided you don't move it around.

Staples stuff they sell in the store, particularly office furniture, for the most part is garbage. Its meant to be a desk you spend a little bit of time at, not work full time at. There is a reason real office furniture is expensive. That goes for your chair too.

None of the stuff is rocket science to build, its all insert tab A into slot B. If you have a screw driver and a hammer you are good to go.

A REAL desk that isn't going to come apart on you in a few years and shows up put together is going to be north of 4 figures. That is why they are so expensive, the shipping and delivery of it.

The dude who builds your staples furniture is probably making 15 bucks an hour and cranking out a half dozen pieces an hour.