[.....]
So now instead of getting the 0.01 BTC from my wallet, exactly 0.01 BTC worth of SWARMPRE have been sold and that is the balance of my CP BTC wallet (the transaction I sent however seems to have evaporated into thin air)
Whenever you do ANYTHING on CP, you pay a transaction fee that is non-refundable, you can think about the fee like the stamp that lets your XCP order ride in its bitcoin envelope on the bitcoin blockchain. So the inability to cancel your order is because you lack the money for the stamp with which to submit your order to the blockchain.
This means it is fairlye xpensive to do anything because the dust limit and miner fee puts the minimum size at fairly high. This is why other chains are being developed, for lower cost easier trading.
Is there a a fee table or something?
And are there transactions/processes that cost nothing?
In other words: What costs how much? Is there a summary of this anywhere?
Most transactions are about US $0.06. If you're selling BTC on the DEx, you pay about 1% of the amount as anti-spam fees to Bitcoin miners (not us!).
And is it always the cost in XCP (0,06) + tx fees to bitcoin miners?
Does anything on the DEX cost? I mean if I am selling BTC then often for an asset...
No, the six US cents are in Bitcoin tx fees. There aren't any XCP fees at all, except 0.5 XCP for every initial asset creation.
Can you explain how the transaction fee is different from the "anti-spam fee"? Was this an agreement reached between Counterparty and Bitcoin mining pools/devs, or ...?
The transaction fees are set by Bitcoin miners and are independent of Counterparty. The 0.5 XCP anti-spam measure we set up, and the miners have nothing to do with.
Well AFAIK the mining fee in the reference Bitcoin client is set corresponding to the size of the transaction in kb and coin-age, not transaction amount, and should be the same whether the transaction sends .001 BTC or 100 BTC. So how/why is the fee about 1% of the transaction for some transactions, and not just $0.06 for every transaction?
It's part of the Counterparty protocol to prevent troll orders on the XXX/BTC DEx. It's only for orders involving BTC.