Friend gave me a $25 gift card. She is very poor financially. I know she means well. But how can I return it to her for her to use for herself. I know this isn't kosher. But I am financially ok?

Acknowledged your gift and use it on her. Breakfast, lunch or dinner. Please stop talking about how poor financially she is. She knows her wealth.

Take the card and buy her something as well.

That gift is an expression of how much you mean to her.

To return it would be to tell her either that she is wrong and / or that her gift is unappreciated.

Now what do you want to do?

You don't need to return it .. I'm thinking that may hurt her feelings. She was willing to sacrifice it for you .. that is the gift .. the sacrifice, not the money. 

Take it and be grateful and gracious knowing that she went through the trouble of getting it for you. 

In return, Take her out for meal (your treat) or buy her a gift her an equitable gift, or just do something nice for her. 

If I were you, I would take the gift card with a big smile on my face, I would tell her in person how much I'm thankful for and I would text her again in the following day.

I would not buy her something cost more than $25 or take her to fancy course, coz she may feel "oh I cant afford that, what should I gift next? He just raised the bar higher" so lets stay with $25 while she's struggling. What I would do, I take her to mid class course but for couple of times, like once a month for her $25 and her efforts too, I think she deserves that.

And you know she's struggling, motivate her mentally and be a good friend and never lend your money for her coz it may ruin your friendship.

Ugh you're so lucky for having this kind of friend :)