Are you doing 'maker classes' for kids, or are you making and selling toys that help them learn on their own?

If you're doing classes, the only way to sustainably scale up is to make sure that a majority of your classes are using digital maker tools, instead of physical ones. For instance, using https://scratch.mit.edu instead of Lego Mindstorms. This is because scaling up with digital tools will be enormously easier than dealing with physical inventory: No need to buy / keep track of / store / transport, etc., no need to do on-location training of new instructors (they can train at home), etc.

If you're not doing classes, but are instead making toys for kids, again a software product would allow easier scaling, but if that's not possible for you, then you're going to have to work on getting into retail shops and/or increasing your online presence in the maker space.

Feel free to send more background info if you'd like advice more tailored to your specific problem,

best of luck,

Lee