I have heard from several sources that plants from private nurseries doesnt always turn true to what they said it is. Example, they might give Banganpally if i ask for Alphonso, and i wouldn’t know it until 5 years after. The plants from government institutes are too small compared to private nurseries and are of the same cost.
Buy from Govt. or Agri. Institutes nurseries , grow them in bigger grow bags for 3 to 6 months and plant them in the field.
Ask them to show the parent plant and the history of the saplings. This way you can get an idea.
Any saplings which is 0.5 ft to 1.5 ft is good enough for growing.