Welcome to the forum
Bitcointalk only accept 1 altcoin named Grin, the copper membership right now is 0.00052935 BTC if you pay with Grin it cost 105.870000000 grin.
To send via grin you need to follow this command
Use a command like grin-wallet send -m file -d btct1.txt 105.870000000, and then copy/paste btct1.txt into this box.
https://bitcointalk.org/index.php?action=credit;fund