When you are camping or going on a trip or a hike, it is important to be prepared in advance. A lot depends on what can be recommended for you. Sleeping bags are really important for any traveler.
And yes, you have a big choice. There is one for cold weather, hot weather, humid weather, rainy weather, etc. You may try using Aegismax down bag for your trekking purpose. It has good reviews for its quality.
Therefore you will need to buy a sleeping bag that will keep you very warm in very cold weather with all kinds of layers to ensure that your body temperature is maintained; if not cold, but warm, then you need a roomy sleeping bag so you do not sweat in.
Many of the same case with the humid weather. If the weather is rainy, your bag should be such as would prevent rainwater soaks your bags, and also keeps you dry.
If you are the occasional trekker and generally stick to the general temperature region, then the obvious choice would be a sleeping bag, which allows you to breathe. It has vents at the bottom of your feet, and not as close-fitting as the 'cold' weather.
Whichever bag you buy, make sure you buy good quality. A little more expensive today will save you dollars tomorrow! Buy one that allows you to use a mild detergent after use, and dry them off as soon as you get back. Good care of a sleeping bag will help you save more in the long run.