To define any column in a table as a list or an array, you can simply specify the column type with an empty set of parentheses, (), on definition. Following this definition, you can then upsert the price array along with the time value, and the column value for that table will be assigned to a float list type (upper-case F in meta command indicates the column is a list of floats, as opposed to a float atom which would be identified with a lower case f):
q)t:([]time:`time$();price:())
q)`t upsert (.z.t;60.57 60.61) `t
q)t
time price
------------------------
21:47:06.298 60.57 60.61
q)meta t
c | t f a
-----| -----
time | t
price| F