A pile and a mound are more or less interchangable, although a mound imfers a more rounded and compact shape to me, whereas a pile will not have such a uniform shape to it. A drift, when used to describe a large quantity, is only used to describe snow that has been blown into a pile/mound by the wind.

1."pile" "mound" "heap" :they can be used changeable. a ~ of sth, put sth in a ~, 2."bundle'' , "stack" as the meaning of "a lot of", which may be in order a bundle of magazines( the magazines are packed in bundle) 3.when they are usd for money ,and other invisible things, each is ok.

Pile and mound both mean a gathering of inanimate objects, such as a pile of sticks, or a mound of dirt. The word 'drift' means to 'go away from', as in 'The boat drifted away (from me) in the water.'