I had a similar search recently. To be honest, I had to dig around because many sellers overcharge if the float is below 0.03. In the end, I found the best option on https://dmarket.com/csgo-skins/product-card/gut-knife-marble-fade . Unlike other sites, here you can immediately see what you are buying, and this saves time. So my advice: just monitor dmarket, and the knife you need will definitely appear.