Hello,

Answering your questions in order:

I went to coinpayment prices, but could not understand it much better.
In their prices, I will be charged 0.50% while recieving payments.
If I use this plugin, will I also be charged 0.05%.

Yes, when depositing using the CoinPayments adapter, a fee of 0.50% is charged. Deposits are done to callback addresses.

In addition, if a user sends coin to another user using their username or email address, will I be charged?

No, the only fees charged when transferring to another user are the proportional fees that you specify in the coin adapter settings. The setting is at Wallets -> CoinPayments -> Fees -> Move fee (proportional).

If also, a user send coin to other user on that same site using the wallet address of the reciever, will it be a charge also?

If you attempt to withdraw to a deposit address of a user on the same site, you will find that an internal transfer will be performed instead. So the same move fees will be applied as described above.

I asked this, because I don’t know also in which transactions on the site do IPN calls are made.

IPNs are the callback mechanism that the CoinPayments service sends to the plugin to notify that a deposit has occurred.

Hope this answers your questions. Do let me know if you have any more questions.

kind regards,
Alex

P.S. I have transferred your post to the CoinPayments support forum because it is not relevant to the WooCommerce extension.