Frankly, if you do not have the space and money to accommodate all the resulting newborn guppies, then leave the babies to be fed to the adults. As nasty as it sounds, how do you expect to accommodate everyone if you keep saving every new fry and later on, get overwhelmed by the number of fish? Guppies are not known as "million fish" for nothing at all. They can drop an average of 15-50 fry per batch. Do you really think you can support thousands of them in a few months? That's something I would not waste time unless you have other fish whom you can feed the guppies to.