pre-assembled or flat-packed
The kitchen units you choose depends on a number of factors, apart from the overall look. Assembled units (or rigid carcasses) usually cost more, are quicker to fit, have less chance of bits missing, and are perceived to be structurally superior. Modern flat-pack carcasses tend to be made on a CNC machine, which improves the chances of holes for screws etc. lining up. They are also initially cheaper (although allow more for fitting, unless you are doing it yourself ). You need space to take delivery of assembled units, or to unbox and assemble flatpack ones. Most DIY sheds and kitchen suppliers offer both within their ranges, with many fitters believing a decent flatpack kitchen is better than an inexpensive assembled one.
Below Metod kitchen with Veddinge Grey doors, from £36 for a w40xd60cm base cabinet; Ivar shelving units, from £76 each; all Ikea