I don't buy things that I think are indecent or offensive, but certainly I'll let dd buy things that I don't especially find attractive. I'm not the one wearing them, she is. She's going to be an adult in a few short years. I think it's OK to let her have a little control over her wardrobe.
ITA and this is how it is in my house. My dd knows what we allow as far as appropriateness and as long as it falls under that, she is allowed to pick out whatever she wants, it doesn't matter if I'm paying, she's the one wearing it. I want her to express herself with her own style and be comfortable in what she wears, not what style I think she should. I'll give her an opinion, like what color I like or what I think looks best on her, but its ultimately her choice.