Your choice of bike pannier or basket will depend on where you want to fit it (handlebars or pannier rack) and how much waterproofing you need.
1. Front or Back Fixation?
If you want to keep an eye on your belongings or distribute the weight, what's the best solution?
Panniers are generally fitted to the back of a bike, on a pannier rack.
You can get single panniers (that take up just one side of the rack) as well as double ones (that take up both sides). The capacity will vary depending on the model you choose.
It is generally given in litres for panniers and in kilos for baskets.
Front baskets are practical because you can always see them, but they can't hold very much. Generally the maximum load is 5 kg, with a 12-litre volume.
Some metal or fabric baskets fix to the front of the bike on the handlebars themselves. For other metal baskets, you have to use a front or rear pannier rack. Make sure you check that your basket is compatible before you buy it!
If you use your bike regularly to get around, waterproofing shouldn't be overlooked. It might seem like an optional extra when buying your basket, but you'll soon change your mind after the first downpour!
Reminder: don't mix up water repellency and waterproofing. Water repellency is the fabric's ability to "pool" water on its surface. The faster the water runs off without soaking into the fabric, the higher its water repellency. It could therefore end up getting through the fabric.
Waterproofing is the fabric's ability to prevent any water, from rain to snow, dew and water vapour, from penetrating it.