I have recently had experience both buying and selling on thredup. My first order with thredup was kind of a bust and I ended up returning most of the items of women's clothing. I was promptly given a refund. Subsequent smaller orders have been excellent, including an awesome Guess coat! Quality is very good and most of the prices are excellent.
I sent in two bags of clothing and received a little over $75, which I promptly turned around and ordered more clothing valued over $500 ;) As someone who has sold on eBay, you have to keep in mind all the time + fees you take on when using that method of selling. Clothes are like cars, once they leave the store, most of their value is lost!