You want me to pay $30 for a pdf of a retroclone that hasn't had any updates in 4 years???

It is my understanding that this is a standalone game that might not require updates. You might argue about the end of support of its modules and supplements but this is the fate of all games overtime, ain't it? 

Still, it is a product on its own. Rules-wise, you may check its SRD for free if you want (https://lucasrolim.itch.io/minibx-srd)