spend (something) on (someone or something)
1. To spend some amount of money in order to pay for some product or service. I'd be willing to spend around $1,000 at most on a new refrigerator. If you spend the bare minimum on your computer, you can't expect it to give you top-of-the-line performance. It's insane to me that you have to spend tens of thousands of dollars on college education.
2. To spend some amount of money for the benefit of someone else. I feel like my girlfriends spends too much money on me, but she always brushes it aside whenever I bring it up. My parents could never spend much on us when we were growing up, so I'm always a little incredulous toward parents who buy their kids whatever they want.
3. To expend some amount of time doing or working on This new operating system is so large that you should expect to spend a couple hours on the installation. I make a point of spending an hour each day on yoga and meditation. The reports should just be summaries, so don't spend too much time on them.
spend something on someone or something
to pay out an amount of money for the benefit of someone or something. How much did you spend on him for his birthday? I spent a lot on Mary's gift.