You can absolutely give her a gift card for the grocery store or whatever. If that’s what she needs now especially with all of the Rona mess going on, by all means.
Mid 30s woman myself, I pride myself on my gift giving. I don’t just want stuff, but if you see something and think of me, by all means. I keep a running list of “stuff people like” on my phone. Family, friends, etc. I’m not saying that’s what everyone should do, but I do suggest if you spend a lot of time with the gal, reflect on it. It doesn’t need to be big, but people like to be considered, thought of. A rando “neat sounding local jean company“ was mentioned to me by my husband. A year later, I got him a pair.
What are her hobbies, or as a single mom, what would she like them to be? What does she like to do to unwind? Does she wish she could buy some fancy makeup, hair, face, thing? Get her a gift card to sephora, ulta, or something. Cash alone won’t show that you think about her. Gift cards are good for places you know she’d like to spend money, but you aren’t versed enough to pick out something. Maybe a couple different gift cards, but making one of them for a place she can’t possibly buy something for her kids. or maybe cash and some small thing you recall her saying she liked. That money will be helpful AF right now, but that thoughtful object will mean just as much.
sorry for rambling.