When foraging for mushrooms it is important to have the right type of container to use when carrying and transporting your crop of mushrooms back to your home ready for dinner. If you were to use a plastic bag then the mushrooms would sweat and wouldn't keep fresh for very long, and would probably look and taste not that great. A paper bag would be a better bet, but again the mushroom wouldn't be able to breathe very well. The ideal solution is to use a wooden basket, and this is the number one choice for most serious mushroom pickers.
Although it may appear to be quite cumbersome and embarrasing to carry around with you (it is also a very good tool at letting just about everyone know what it is that you are up to - and perhaps alerting a mushroom lover that there are edible fungi nearby), a mushroom basket enables you to pick your selected mushrooms and lay them in a basket where they will get plenty of air circulating so that they can breathe adequately. Some people believe that by using a wooden basket (which will inevitably have little gaps between all of the wooven pieces of stick) you are enabling the collected mushrooms to continue to drop their spores right through the basket and onto the woodland floor as you walk around carrying them. This, although it may seem quite possible, is extremely unlikely. But it still doesn't do anyone any harm, and as its probably the best way to carry mushrooms then it doesn't really matter if its true or not.

The best kind of mushroom basket to get is one made from a wood such as hazel or beech. The size of the basket should be dependant on you rown personal requirements. If you are picking for you and your family then you will want something quite large. If you don't have many people to feed then you won't need anything too big, and you don't want to be unnecessarly be carrying around an over-sized basket which is only going to contain a couple of Chanterreles and a few Ceps. Whatever sort of size you deem necessary should be adequate, but remember that you are probably going to be kicking yourself if you are lucky enough to encounter a giant puffball, followed by a field full of ceps, etc. Its probably best to over-estimate the size of your basket then to under-estimate it.
A decent, well made, well cared for mushroom basket should last for many years so you won't have to go out spending money on newer models. Most mushroom baskets have been treated and varnished so that water can't do any damage to the wood, and this should be labelled on the basket by the manufacturer. A good mushroom basket could cost you about £20.