Good paint edger tools include the Accubrush edge-painting tool and the Shur-Line paint edger. Both tools make it possible to paint straight edges without relying on painter's tape.
The Accubrush uses edged rollers to apply a smooth, straight edge along moldings. Attaching the tool to a painting pole makes it possible to cut in the ceiling edges without needing to stand on a ladder. The Accubrush costs from $40 to about $125, depending on the package chosen, as of 2015. Some finishing with a brush may be required.
The Shur-Line paint edger consists of a flat, absorbent pad that transfers paint to the wall by rolling it along the ceiling or trim edge to be painted. The result is a smooth, consistent line of paint that doesn't require tape or a paintbrush.