I would certainly say drinks stall. However, the use of singular or plural forms is fraught with anomalies. For example, a pair of trousers is...or are (and there you go!)...clearly a single garment and, within the tailoring trade itself, it would not be unknown for someone to refer to "a trouser".
As J suggests above, it is probably best just to go with the version that sounds 'right' to YOU. English does not have the equivalent of the Académie Française, which lays down the law on what is correct. Mind you, the French just ignore the experts when it suits them!