Hey bucutie02,
I got my mom a Spa thing last year, however, instead of the whole day at the spa treatment, I just got her a pedicure and manicure gift certificate. She loved it cuz she loves having her feet massaged and stuff

So maybe if you can't really afford the Day at the Spa, maybe get her like a facial and manicure or a combo of some things. Or maybe even just a massage...massages are definitely worthwhile
Other ideas...jewelry, clothing, something for the house (a painting, vase, etc), something engraved, miniatures/collectibles (maybe if your mom doesn't collect stuff, you can start her off w/ collecting something like little dolls, etc. My mom collects mini clocks...they're so cute!), hmmm, or anything personalized. Parents are so hard to shop for sometimes. I know shopping for my mom is so difficult cuz she owns everything!!

But I hope that sparked some ideas for ya.