Shopping for a Paddle
Shopping for a paddle is part of an important decision to make too. Like a rifle, without it a soldier will be defenseless. There are several factors to be taken into consideration.
Length :
The first decision you have to make – is what length it is going to have.
The best way to find out is to try paddles of different lengths. You might be able to borrow paddles from other rowers and try rowing with it. See if the length suits you. One way to measure is to place the paddle vertically at your toe and try using your hand to reach out to the top end of the paddle. Your arm must be straight.
Angle:
Every blade has different angle. This will affect the time elapse of your paddle water entry & exit, and also the efficiency of stroke and body rotation. Test it out of other paddlers's paddle, seek their comment on it.

Weight:
Every paddle depending on manufacturers, has different weight or lightness due to different process of making, different material used and material grade. Always ask for weight and what material its made of.
Types:
There are many different types of paddle in terms of brand, quality and sizes.

Do not be over-concern with brands. Every paddle are moulded and built for each individual style. So never compromise on function & performance than on-to branded paddle.
A paddle's first paddle is the crucial part. Because this is the paddle that he/she will train and row with for as long as the passion remains. Paddles has many sizes from mini to max for beginners to professionals. Its paddle has different angle of degree too. This will affect how a paddler row in its stroking and body rotation as well as water entry and exit.

For beginners, I would recommand small size blades. (BRASCA IV MIN) This helps to get stroking and techniques right rather than pulling water & wasting efforts.
However, if you are a pro or about to obtain that level, you may want to consider using bigger paddle with bigger blades to maximise water catchment.