toolic has identified the basic problem. These ramblings are for your consideration (in light of the self-characterization in your home node):

You appear to be passing variables --$count and $newPrices{key} -- into getFiles() as arguments to the call. By doing it that way, your sub changes their values in main and in the sub. For example, if the first file has three lines and the second has four, and if the value of $count in main is 0 on entry to the sub, its value will be 7 when you return from the sub. That's probably a non-issue in the particular case, but it's a behavior of which you want to be aware.

You've also written a sub with no explicit return which means the sub may do something you're not expecting, as explained in perlsub:

"If no "return" is found and if the last statement is an expression, its value is returned."

All in all, then, I commend a close reading of perlsub re return and also with special attention to the explanation of passing variables by reference.

Update: clarifiation, p2, sentence 2 and fixed markup.