WESCO's Blocmodules package comes from France. The system is modular and a relatively low investment will get you started. There is a good choice of shapes and sizes. The pieces are made from high-grade foam, with a waterproof fire retardant polyester cover. They are light enough for children to move around, with the added bonus of the chance to explore construction and 3D maths.
The Lifetime Company toured Europe and discovered a brilliant German soft-play package called Dublup. It has developed three versions for three age-groups, all compact enough to be a permanent feature of the early-years classroom. Dublup can be used as bright and comfortable seating when not serving in a more active role.
A basic unit comprises two chains of red and yellow foam prisms which are linked with PVC hinges so the user can fold and interlock the chains. This simplicity allows all sorts of inversions and rotations of shape and promotes imaginative play.
The Dublup ball-pool set is genuinely portable and big enough for three to four children (or one silly grown-up and two youngsters). The blocks surround a cleverly designed draw-string bag for the ball-pool. Setting the pool out is a few minutes' work and the package stows away tidily. The experience, which stimulates the imagination and gives a sense of being in a swimming pool, attracts adults just as strongly as children. You can expect to find staff in the pool, while children stare from the banks.
If space is not a problem and you want to make soft-play a permanent feature, NES Arnold supplies a Soft-Play Activity Set system which includes padded wall panels.
Soft-play materials give children the confidence to try out their tumbling and gymnastic talents. It is advisable to invest in perimeter safety matting. Just in case.