Waste or spend?

What's the difference between "spend" & "waste" in these two sentences?

She spends a lot of money on clothes.
Buying clothes? That's a waste of money!

Thanks in advance.

"Waste money" means to spend money without getting something equally valuable or useful in return. However, it is possible to spend a lot of money on something and still get a fair price. "She" may spend a lot of money on clothes because she has a large family, or because she has to wear formal clothes for her job - this is not wasting money. However, if she spends a lot on clothes that she never wears (the clothes are not useful), or the clothes she buys are overpriced (the clothes are not valuable), then she has wasted her money.

I think, the difference between "waste" and "spend" is in the connotation.
"Waste" has the negative connotation of useless loss (of money), "spend" is pretty much neutral.

^ That's right.

'She has spent a lot of money on clothes.'
— completely neutral; simply describes what she's done

'She has wasted a lot of money on clothes.'
— negative; suggests that she shouldn't really have used a lot of money for clothes, perhaps because she doesn't need them, or because the clothes were not worth what she paid.

<negative; suggests that she shouldn't really have used a lot of money for clothes, perhaps because she doesn't need them, or because the clothes were not worth what she paid.>.
...or perhaps she should've spent this money on something much more important as on finding a good doctor for her sick child. The use of 'waste' emphasizes a reproach from a speaker's viewpoint.