One of the best things about party planning supply stores is that you can make it completely your own. Some companies allow you to upload your own art or graphics to be printed on invitations, napkins, plates, bags, masks, cups, and other accessories. You can choose your colors, a theme, and select from a variety of different styles of products. On the other hand, if you want to keep things simple, party planning supply stores also offer a wide range of products that look amazing without having to customize them.