You only need little equipment to play badminton.
This has two literal meanings, both of which seem odd:
Clearly the writer did not intend either of these meanings. First of all there is obviously a standard size for badminton equipment, which is neither small nor large. Secondly, it would be impossible to play badminton without ‘enough’ equipment!
Little and a little have quite different meanings. Compare:
In the opening example, the writer is – I think – trying to say that playing badminton does not involve a lot of equipment:
In this case, not much means enough, and that’s good because it means that badminton is inexpensive compared to, say, photography, which generally involves a lot of expensive equipment and therefore a lot of spending!