There are four grades of wood: Prime, Select, Nature and Rustic grade. Make sure you compare like-for-like in order to get the best value for money.
There are significant differences between different grades which could ultimately affect the look of your project.
Clean uniform appearance with minimal knots, sap and colour variation.
Presents natural characteristics with some knots and minor colour variation.
Broad range of natural characteristics.
(Often known as Character or barn grade) for a rough and casual look. In short, the lower you go in terms of grade, the more rustic finish the wood has.