Create a Graph is very simple to use web based Graph Generator that I can highly recommend for younger students who may find a spreadsheet such as Excel a little daunting. A very simple interface lets you select from Bar, Line, X&Y, Area and Pie graphs and takes you through each stage of the graph making process in simple to understand language.
There are examples and tutorials, not that you will need them and you can output graphs as either a traditional paper based printout or get a hyperlink to view your graph online.
Be sure to take a look at Create a Graph next time you are doing a statistics and data lesson with your kids and want to generate a graph simply whilst teaching your kids the steps required along the way.It's free of course with no sign up required and there are a few other useful tools to be found on this site also.
By the way if you are looking for a great lesson plan on Creating Pictographs on Computer with younger students. Here is one from my lesson plan section.