1 The cheapest shelving is old 150 mm x 25 mm (6 inch x 1 inch) floor boards salvaged from builders' skips. The cheapest way of using them is to lay them across dry-stacked piles of bricks.
2 If you want to buy new shelving, pine boards from a timber yard or builders' merchant are cheaper and nicer than Melamine-covered chipboard from DIY stores. They are available up to 225 mm (9 inches) wide.
3 Angle brackets are a quick way of putting up a single shelf, but it is not easy to get them level, or securely fixed. Proprietary systems such as Spur shelving are probably easier, and are generally cheaper at builders' merchants than DIY stores.
4 If you are supporting a shelf across two supports then each should be one-sixth of the span in from the ends. Always use a spirit level to get the supports plumb (vertical) and level.
5 Use plastic plugs to fix into brick walls, but don't try to get a fixing in the plaster; tap the plugs through into the brickwork beneath. If you can't get a good fixing, check that you are using the correct-sized drill bit and screw for the plug.