What is a good price for kids clothing? (New, per piece) in comments, good price for used items?

This is my first baby so I’m completely new to the market and clueless as to what is/isn’t a good price. Especially for babies and how quickly they grow, I’m kind of thrown by how expensive baby clothes can be. I love styles of Zara, Bailey’s Blossoms, and H&M, and Etsy has some adorable pieces too, but I’m a momma on a budget so definitely want to make sure I’m getting the biggest bang for my buck. I don’t shop at Walmart.

I do plan on buying used as well, so good pricing for used clothes (in good condition) would be super helpful too!