Any ideas to celebrate valentine that too in a small budget??

Spend your remaining money on buying pirated DVDs or go rent some movies on your local movie rental shops. Celebrate it with your partner at home on a movie marathon. If possible, rent only romantic movies. Horror movies are great too to add thrill. You can eat food that's available at home or you can buy some chips and 2 bottles of Coke. Also if you have money left, go buy her a simple Valentine's card. I'm pretty sure she will appreciate your effort.

First thing you can do is make the card. people always prefer the hand made stuff because it takes time and shows caring. Perhaps you can also make her dinner. It is much cheaper then going out to a restaurant. Flowers are also nice but don't go to the florist. You can usually find great deals on them at the grocery store of all places. Just some ideas, good luck.