THORChain has no flat trading fee. Every swap pays a liquidity fee that depends on how much of the pool it consumes: a $500 swap into a deep Bitcoin pool costs a few basis points, while a $500,000 swap into a thin pool costs far more, and the commonly quoted range is 5 to 50 basis points. Streaming swaps split a large order into many small ones over several blocks to hold the fee near the low end, which is the mechanism that lets THORChain handle size. The fee is paid to the pool's liquidity providers and to the network, in RUNE.
On top of that comes the outbound fee, which is THORChain paying gas on the destination chain to deliver your asset and charging you for it with a dynamic multiplier that has run between roughly one and three times the raw cost depending on network conditions. When Ethereum gas spikes, the outbound fee on an ETH swap spikes with it. And on top of that comes the affiliate fee the interface you used has registered, set in basis points by the interface itself and varying by front end and by tier; interfaces publish their own schedules, and those schedules have changed over time.
What none of those fees cover is getting dollars into crypto, because THORChain cannot do it. Anytime Capital is priced for that step: card orders from 4% with the spread included, one all-in number with the amount you pay and the crypto you receive shown before you confirm, and ACH, wire and cash priced the same transparent way, with Bitcoin and Ethereum each on their own buy page. It is a buying fee, not a swap fee, and it is the one THORChain cannot charge.