i Tunes "allows" up to 5 computers to share.
I use plastic pre paid vouchers to pay.I have two "accounts"
On the new computer install iTunes by downloading. Then go to Store and create the same account that you use on the first PC. Then copy your music (on original PC in iTunes/ iTunes Music) to a USB HD or DVD's. Then on laptop go to i Tunes/ Music, then "Add folder to the library" and add the folder from the USB Hdd or DVD's. If you have a network you could do it that way.