Again the verb here is not a command, though it appears that way in all English translations. It is a statement about what "should" or "might" happen. Since the negative is one of opinion, the "should" seems most appropriate. the future. This doesn't mean that they shouldn't bring money, but that they shouldn't make money. It is a followup to the "freely given" line.
The words for "gold," "silver," and "brass/copper" have double meanings. The first covers everything precious, the second covers all money, and the third also means military arms. The words for silver, brass, and purse are only used by Jesus here. People in Jesus's time didn't use "purses." They rolled up their money in their belts. -
Christ's Words in Matthew as a Guide to 40 Days of Prayer.