The problem comes from two pieces rubbing together. Either the material is not clamped tight enough, and cannot be due to the material or fasteners used, or there is too much flex in the piece itself (not braced properly). IKEA furniture being flat packed and "easy to assemble" combined with the pricing has this kind of issue as an inherent flaw.
If you switch from pine and particle board with veneer price goes up, change certain fasteners or joinery, complications happen with assembly or the ability to flat pack.
The best advice I would say is see where the movement is in the piece and brace those joints to limit movement. Then the squeaks should be gone. Or you could lube it up with some WD40 ;).