Affordable but meaningful Valentine’s Day gift ideas for my mom?

Take her on a date, if you can scrounge up enough money to go to a restaurant. Or, if you're living on campus, see if there's a room or area you can reserve and make dinner for her, perhaps with candles and a single rose in a vase on the table. Make it about her; ask her to tell you about herself: growing up, what were her aspirations? Who were her heroines and/or heroes? Fondest memories? Embarrassing moments? First love? First date? If there are things you've never known about your mom, ask her to tell you these things.

My mom never really talked about her life as a kid. She devoted herself to me and my three siblings while working full-time and dealing with a husband fighting his own demons and not being quite the partner she had longed to have. (That eventually changed, I'm glad to say.) So, during my college years, I took her to dinner once at a decent restaurant and asked her about her childhood. I learned a lot about her and grew closer as a result.