(a) 15 gm more in every 500 gm pack - yes, it will benefit because it is given at the time of purchase.
(b) Subscribe for a newspaper with a gift at the end of a year - no, because you have to keep paying every month for one year without any guarantee that you will get the gift at the end of the year.
© Scratch and win gifts worth Rs 10 lakh - no, as you can scratch the card only after purchasing and in most cases you will get nothing.
(d) A milk chocolate inside a 500 gram glucose box - Yes, as it is a usable benefit being provided with the pack.
(e) Win a gold coin inside a pack - it may not benefit the consumer as the possibility of being lucky to win a gold coin is very low as only a few coins, may be 5-10 will be placed in about thousands or lakhs of pieces.
(f) Buy shoes worth Rs 2000 and get one pair of shoes worth Rs 500 free - the shoes may not be of the style and standard required by the consumer. Also, the price of Rs 2000 may have been increased to include the cost of the shoe of Rs 500. So probably the consumer is not benefitted.