Buying your first boom pole is a very good investment with good maintenance, lasting years. Buying your first one you are mainly going to be focused on price and length of the pole. It's very advantageous to have at least 3 meters for most situations. Later like me you will have 2 poles, one for shorter, just out of reach distances and one thats 5 meters or so more heavy drama work.
The most trusted starter on the market is the Rode Boom Pole. It is a bit heavier than higher quality poles at just under 1kg will get you in good shape later down the line and going from 0.84m to 3m it will cover you for 95% of film work, whether you are one man banding or in a team.
Buy from amazon directly to save over £50 RRP.