If bonus shares are sell within a year from the date of allotment of bonus share, than short term capital gain arises.
Sell Value: at the prise you agree to sell with buyer
Cost: Nil
ST Capital Gain: Sell-Cost
Long Term Capital Gain (If sell after 1 year from the date of allotment)
Sell Value: at the prise you agree to sell with buyer
Cost: Nil
LTCG: Sell-Cost