Budget kits (1.5Kg) are made using lower grades of malt extract and sometimes barley extract. These kits usually require the addition of sugar or can be enhanced by replacing some or all of the sugar with malt extract in liquid or powder form. Budget kits are ideal for experimentation with additives or as a base to create your own beer style.
Midrange kits (1.7Kg - 2.1Kg) are made using a higher quality malt extract than the Budget kits. Sugar is needed to achieve the desired O.G. or a combination of sugar and/or malt extract which will produce a fuller bodied, maltier flavoured, beer.