(2) If I bear a non interest account of a interest based bank and take their discount offer from different product, is it legal in Islam?
بسم الله الرحمن الرحيم
(1) The ruling pertaining to interest money is that it should be given in charity to the poor and needy ones without an intention of reward, this money may also be given to a non-Muslim poor. However, you will not get the reward of doing charity and you should not make the intention of getting reward as well. However, it is possible that you get the reward of following the Shariah command.
(2) What is the procedure of taking offers, explain it and submit your question again, then we will have a say in this regard.
Allah knows Best!
Darul Uloom Deoband