The least order volume may perhaps range since it depends on the preferred fiat gateway. Usually, the minimum order starts at $20 (or the equivalent volume in your local fiat currency). There were quite a few times when I clicked within the “Support” link only for being navigated again https://financefeeds.com/bitcoin-reclaims-86k-as-trump-demands-rate-cut-can-btc-hit-100k-in-april/