Hey Prateek,
You can visit Leh via road only from June to October as in rest of the months road get blocked due to snowfall.
Ladakh trip cost :
1) Via Road in June to October ( only time when roads remain open )
a)Bike on Rent from Delhi : It will cost you total 20k per person if you go with your friend on single bike.
b) Sharing Jeep from Manali : it will cost you approx 18k per person.
2)Via Air in rest of the months
It will depend on air tickets( normally 5k per person from Delhi). Then it will cost you total 20k per person.
This all is rough idea of cost. So always keep +5k extra with you.
You can also do a round trip Delhi to Manali to Leh to Srinagar to Delhi :
Day 1 &2 Delhi to Manali to Leh
Day3 Local sightseeing - Hall of Fame, Shanti Stupa, Gurudwara Pathar Sahib, Thikse monastery, Leh Palace
Day4 Rafting In Zanskar river- Highest point for rafting in the world
Day5&6&7 Khardung La pass, Nubra Valley, Pangong Tso
Day8 Leh to Srinagar
Day9&10&11 Srinagar, Gulmarg, Pahalgam
Day12 Srinagar to Jammu
Day13 Jammu to Delhi
Happy Travelling!!!!!!!