This is what the manual says about defining arrays:

4.5. Arrays


Variable arrays can be created in a similar manner to variables.


Label VAR Size[Number of elements]


Label is any identifier, excluding keywords, as described above. Size is BIT, BYTE or WORD. Number of elements is how many array locations is desired.
It is not clear if the Number of elements has to be a literal number or a variable can be used.

Can I do something like this?

Code:
READ 1, num_books ' how many nooks
books VAR BYTE[num_books] ' Define array for each book price