Hey Nelson, If you go by government buses and stay at cheap hostels or zostels then it would cost you approx 8-10k per person for 3 days stay at Manali including the activities like skiing and rafting. ■ Places you must visit in Manali : 1)Solang Valley 2)Hadimba temple, Mani temple 3)Vashisht hot water springs 4)Jogini waterfalls, Rahala waterfalls 5)Gulaba 6)Rohtang pass ( closed in winters) 7)Bijli Mahadev trek 8)Skiing, Rafting, Paragliding Hope this would help you.
Day 1 delhi manali ( will cost 1k something )
day 2 stay in hostel ( 500 rs - 600 rs and food charges) - check out on foot hadimba temple , nature park, mall road
day 3 stay in hostel and catch govt bus 8 am to go to solang 650 rs for cable car +2500 paraglide and food charges
day4 stay in hostel and check out on foot jogini waterfall day5 manali delhi bus 7k is way more go for 5 -6k