Er, your poll does not make sense!! Which guppy is best, choices guppy or 3 non-guppies!!
If you mean which of the 4 livebearers you quote, well, it depends, in terms of cheapness, probably guppies since they tend to be smaller hence do not require large quarters.
All 4 are easy to breed.
This really should be in chit chat, it is not an emergency.