This is not a good idea bud, it is not a good idea to give or sell your account out, and neither is it a good idea for anyone interested in buying the account. This account will likely get banned or permanently blocked if or when the management of free bitcoin notices that the account has changed hands through various means like the permanent change of the ip address with which the freebitco system has recognized this account with.
There is no rule saying people are not allowed to sell or buy freebitco accounts.
Read TheQuin's post for more information.
Whilst there is no rule against buying or selling accounts it is very risky for the buyer. It would be very easy for the seller to claim the account was hacked and prove original ownership to get the account back.
I honestly don't remember bans for users using VPNs or the same IP address.
I can confirm this.
I have accessed freebitco using VPN many times and I never had any issues.