Dr. Debabrata Chakrabarti

For A 1 you require more or less 30 classes of 90 minutes' unit. Two times a week, i.e. three months approximately. Max Mueller Bhavan Courses are relatively cheaper than one or other two private institutes. RK Mission is probably the most affordable. It is you who can judge the teaching quality. It will be a wastage of money and time if you don't know beforehand, which one would suit you. So this causes a problem.
Nobody takes the risk of discouraging learning a language at specific institution/institutions publicly. I also won’t. I taught at Calcutta University earlier and could assure you of quality teaching. You could take home a lot. Now my game is over in consequence of my retirement its language department found it challenging to run German language teaching because no competent teacher was available.
A few years ago the German Consul himself told me in a party arranged by somebody about the poor quality of teachers being produced nowadays.
So it is tough to give you proper suggestions. The knowledge of a language other than English/Hindi is limited to a few; and only a few men being judges/spokesmen judgement becomes impossible to get, if they lie.
Better try to seek information from those whom you know to have learnt German.