I'm staying near Manali (Naggar) for almost 2 months now. Naggar-20 Km ahead of Manali towards kullu. 30-35 min drive by personal vehicle or 1 hr by public transport (bus).
Manali is quite over rated in terms of everything. Also accomodation cost would be more over there .
Instead if you stay in Naggar, which is almost equivalent to Manali in terms of geography, tradition, landscape and everything required, it'll be more economical. You can visit Manali anytime you want from Naggar.
Also from Naggar, you can visit many other touched and untouched places like kullu, rumsu, sissu, pulag etc.
I can help you with the stay and itinerary details as well. DM me for detailed one. :)
It totally depends on how you want to stay and eat. if lavishly it would be probably 20-25k . If staying in home stays and having food in dhabas then 10 k is enough.