It is always advised to go for a lightweight binocular. The binoculars must be aligned properly so as to proffer comfort to the eyes. A cheap binocular would be heavy and the lens material used in it would not be of very good quality as there might be some alignment problems in it. Other factors that one must consider when they are buying binoculars is weight of the binoculars, housing of the binoculars, tripod mounting ,comfort of their eyes and focusing power of the binoculars. There are various online shops where you can get big binoculars at very cheap rates and if you are luckier then you might get some discounts also.