Toyshop window display
I've been to a couple of toy museums, and that is how they all seemed to start, from the curators own personnal collection that grew so large that they need a bigger place to display, then they look to opening it up to the paying public to fund more additions, I'm not sure but I think you can apply for goverment subsidies and startup grants for tourist attractions. So you could end up with the government paying for you to collect more toys!