Having used many different chairs and tables and finding which ones make my back ache and my arms go numb, I believe I can state with confidence that:

A table is not a table.

And a chair is not a chair.

Buying a $5 chair that does not even allow the height to adjust is doing yourself a vast disservice in the long run. Desks are not as critical as long as you can adjust the height or install a keyboard/mouse drop down and it holds everything up.