Bro ! dont book travel agency . and money depends on how many people you are going ! idk where you are from ! so from NGP its 300 to gangtok you can have affordable hotels in MG marg around 1000 per day ( if budget is like us ) for 2 3 person ! then ! for sikkim sight seeing its 1500 per car fro four people ! next day day go to Yumthang ! it ll cost about 7 thousands in a sumo ! dn after returning thn go to Tshngpo lake and nathula ! which ll cost you almost the same for a sumo !
I think, March is the perfect month to visit the scenic state of Sikkim. At this time, the winters are almost over, and the summers are just beginning. Hence, you will find the mornings to be pleasant and sunny while the nights will be cold, but bearable. During this time, the temperature ranges between 5 degree to 20 degree. You can reach Sikkim either by flight (which is the easiest way to travel) or by train (which is the cheapest way to travel. Excluding the mode of transport, your trip to Sikkim can cost you anywhere between 10K to 30K, depending on the days you are planning to travel. You should visit Gangtok where you can get the feels of a hill station with good hotels, shops and a mall road. You can visit the breathtaking Tsomgo Lake and Gurudonmar Lake where you can enjoy the panoramic views of the snow-clad mountains. And you must not miss the entrancing Yumthang Valley. You can check out these packages available on Tripoto to plan your trip: https://www.tripoto.com/tour-packages/sikkim