Yes, you can buy during the bear market there is no objection but there is way to buy during the bear market and I think you should follow that because you should be  trading not for survival but for living. In bear market the best place to buy the bitcoin is when there is strong accumulation is going on and you see a strong breakout of the resistance and your entry should be either right at the breakout time or just a candle before it. This entry may give you good return if you really follow it.