I have posted this in Goodwill thread, but I think it works here better
Goodwill is too expensive for me, I buy on Craigslist, or free.
For myself I only buy underwear, bras and socks brand new once a year or two at a retail shop and using discounts and sales. The rest of clothes, if I want to mix-up my wardrobe, I get second hand for free from Craigslist. I'm skinny, so I fit into teen girls clothes perfectly and those are getting thrown away constantly. Teen girls don't want used clothes, which means they have no resell value and I have no completion when they are available for free. I have tons of clothes since I haven't changed much since I was 19, everything still fits and looks great, at that age I was buying quality. My secret is to have tons, so each items gets worn rarely and needs to be washed rarely, that way everything lasts pretty much forever.
For my kids I get very cheap or free, also quality clothes, that I resell after they are done with also on Craigslist for the same price or even more. I have a woman (found her on Craigslist) that I have bought clothes from for my son for the last 6 years and 3 years ago I found one woman who buys those boys clothes from me after my son is done with them. So this arrangement even saves me time on finding the seller and the buyer. I meet with them at around same time each year, we know the drill, it takes no time. So my son's clothes/shoes, snow pants, coats don't cost me anything, I end up making money on selling the items.
I would like to find the same arrangement for my daughter's clothes, but haven't found it yet. So her clothes take a bit more effort to find and then resell, but are also free to me. Similar to me, my kids have a lot of clothes, so each item is worn rarely and therefore in excellent shape for the resell. I only budget about 50$ a year or two for my underwear, bras and socks. Shoes for me are a different story, I do get some for free, but most of my shoes are very high quality, expensive shoes that last for very long time and cost some money. I do buy them on deals and sales, and pay about 50%, but I see that as an investment for many years. I usually don't budget for shoes annually, since they last more than 5 years and rarely I buy a new pair.
Overall my budget for clothes/shoes, socks and so on for 3 people is max 50$ a year. Since there are so many nice clothes in their wardrobe I have never heard them say that they want me to buy them more clothes.