Colloquial, very common in spoken northern Mandarin. Equivalent to 那么多 but with the indefinite plural marker 些 instead of 多. Often carries a slight surprise or complaint about quantity.
grammar
Pair with 这么些 ('this much/many') for proximal use. Both modify uncountable or plural nouns: 那么些钱, 那么些人, 那么些麻烦事.
