From my personal experience i'll tell you the list of some budget friendly and most hospitable place for your conference;-
1.Scope Convention Centre
ADDRESS:-CGO Complex, Pragati Vihar, New Delhi, Delhi 110003
2.Meeting Room Delhi | Training Hall Conference Venue | Tomar Hospitality
ADDRESS:-DMetro Pillar Number 98, 17 A/2 w.e.a karol bagh, Basment Hotel SPB 87 Near, New Delhi, Delhi 110005
3.NCUI Auditorium & Convention Centre
ADDRESS:-August Kranti Marg, Siri Institutional Area, Block A, Nipccd Campus, Hauz Khas, New Delhi, Delhi 110016
Try to get discount by bargaining