Paint is expensive, good paint at least. Maya Hart couldn't do expensive, but that's okay, because there was always the school, and they had good paint. Her art teacher allows her to come into school early in the morning and long after hours to work on her paintings. But she couldn't always be at school. Maya liked to paint at home too, anyways, where she was surrounded by her own things, could play her own music, and scream in frustration when she messed up. She just couldn't do that at school, so Maya bought cheap paint and cheap brushes and cheap canvas. The paint she got on sale for 1.99 a bottle (they were very large bottles) was far too runny and wouldn't stay in the places she put it. The brushes were alright other than the fact that the bristles tended to fall out when she washed them. The canvas was fine, she just didn't have much because it added up. But Maya Hart can make do with what she's got, so she bought some corn starch to thicken her paint, and she was very gentle with her brushes.
But Lucas didn't want that for her, he wanted her to be happy, and with her being able to paint as well as she could without any unnecessary obstacles, would bring her one step closer to it. So Lucas bought her nice paints that came in tubes instead of bottles with a beautiful wooden pallet to mix them on. He bought her dainty paintbrushes, where all the bristles stopped at the same point and didn't come out during cleaning. He bought her several smooth canvases, hoping she might just give one of them back to him, with a priceless picture painted on with care.
Lucas didn't do it to prove he could, or because he pitied her. He did it because he wanted to see what she would do with it.