If you're looking for an affordable date then you can take your partner to Big Yellow Door, Satya Niketan where they have a private place for the couples with curtains around the eating area which would give it a romantic feel, you can also go to Cafe diaries- You can book a space there and ask them for decoration for a price of Rs.500 and more if you want additional things. But it's going to a great experience.
You can also take them to a good garden and have a picnic.
Take them to Dlf, Noida and play sports with them.
You can go and plan to explore a local market and enjoy exploring new adventure or cute things together.
These are some of the things, hope you find it helpful.