Under 10k its a good buy. Lots of power, built like a tank. Good one with good drive for 4 ohms speakers. Not like typical A 616, 656, 717, 757 and 777 were very good with build quality. Much less harsh compared to Pioneer's A 20x, 30x, 40x ... series. Everything inside is of a higher quality so , be aware that if you need to recap, the caps are going to cost a good money.
http://www.hifi-wiki.de/index.php/Pioneer_A-656 if you look at the price in that page, it shows 700 DM, In 1989, according to the inflation chart here
https://inflationsrechner.list-of.info/ 987 DM was equivalent to 1000€ of today, so can say roughly 80k in INR. See the weight and you can see that its not a cheap 6-8 kg british overhyped box now. I said 10k because I bought an unaltered A757 from Chennai 5 years back used for 9k, and in Chennai ritchie street from where all used amps in south india is circulating, it was always around 9k to 15k depending on condition. 10k is a bargain, 15k is decent deal. Above that , I would never buy it.