Engagement parties are not gift-giving events, Save your money for a wedding gift.
Get her a big bouquet of flowers and maybe frame a picture of the couple together or something along those lines
Well I have good news for you then, because an engagement party is not a gift giving occasion! If you feel like you MUST bring something, it doesn't have to be anything more than a card with congratulations, or a bottle of the couple's favorite wine
If you want to send a gift keep it small, a cute cookbook with a personal inscription, wine, or 2 champagne glasses. Dont spend alot. It is a token gift.
Engagement party are not gift giving events. Engagement Party are for both family to get to know each other. If you give a gift, it should be small. A card would be fine.
You do NOT give gifts at an engagement party. You bring a gift to a shower. At most bring a bouquet of flowers or a bottle of wine.