You have the option to set your store's minimum order. For example, if you do not want to accept orders below $1000, then you would set your store minimum order to $1000.
To set your preferences go to your 'Store' settings page and scroll to 'Store Minimum Order': https://merchantshowroom.com/vendor-dashboard/settings/store/ .
Your store's minimum order will show on your store front and buyers will be able to filter search results on category pages based on the minimum order required from the vendor. It is best to not set your minimum orders very high for this reason.
If a buyer tries to check out with less product then your set minimum order, they will see a warning saying that they haven't met the store's minimum order, and they will not be able to check out until they put enough products in their cart to meet your store's minimum order requirement.