Whatever you read was wrong. There is no upgrade required to have multiple galleries on one page in a free hosted WordPress.com blog. To have multiple galleries on the same page you will need to attach all of the images to the page first, and then use short codes to designate which images you want included in each gallery. http://support.wordpress.com/images/gallery/#gallery-shortcode.
After you upload the images go to Media > Library, hover over each image name, note its ID number at the end of the info displayed in the status/progress bar of your browser, then go to the page editor, switch to the HTML editor, and use the gallery shortcode image ID number for the images you want to include.
read also > http://en.blog.wordpress.com/2012/07/12/around-the-carousel-again/