Hi,
If you have strict budget of 12-15K, then better to go for used one. You will get better deals(many IT people in bangalore purchase costly cycles and then stop using it after 2-3 months. they eventualy sell within 1 year because of various reason).
Without Gear: Not recommended for beginners. Better to go with Gears. Leg muscles will get build anyway. With Gear, you will not get tired if u want to go for long distance(more than 5-6 km). Purpose of gear is to keep our rotating speed constant in case of steep climb etc etc.
BSA Deluxe etc: Old cycles were heavy. Current cycles are very light weight. With same amount of energy, you can travel long distance. Current cycles are designed to work for months without giving any issues. Hence costly.
Go through this link for more details about bicycle. If we read more, then we can appreciate why bicycle are costly and what we are getting after spending extra. Frame is the most important component. Shock-up are not needed for city ride. It eats our energy. Good Frame and knee/legs can absort most of the city bumps.
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�Strong. Light. Cheap. Pick two.�
--Keith Bontrager, a bicycle-frame builder and component designer. He now develops components for Trek
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Shop:
https://www.facebook.com/Wheelsportsin-107099686007884/
>>> Venki own this shop. He is very active in cyclying group in bangalore. You can enquire here. He gives good advice.