I assume you want to know what gift to take for the engagement. The best buy would be to invest in a good book about how to know your partner or tips to have a better positive attitude in life. Another good book would be a wedding planner with references of planners of your city.
If you are going on a engagement party then take a flower bouquet with you & also if possible a gift which is a writsh watch for both the guy and the girl. And also remember to wish them with great wishes to them. If not wrist watch then Saree which will impress the girl.
If the couple has created a gift registry then an item from the registry would be a sufficient gift providing that there are gifts on the registry within your price range. If not, then a cash gift in an amount that you are comfortable with would be an advisable gift.