#5 - June 18, 2009, 10:10 p.m.
The accounts themselves can not be merged into one. If you would like a character on your trial account moved to your full version account you would need to pay for the Electronic Upgrade and then pay for a Paid Character Transfer.
The cost versus benefit does not seem to favor making those payments for one trial character, Fujinn.
The trial account would restrict its character from getting past level 20. So we can safely assume the character is anywhere between level 1 and 20. The cost of upgrading to the full version is 20 dollars (usd) and the cost of a transfer is 25 dollars (usd) so you are looking at 45 dollars for one character.
Unless you specifically want to have two accounts that you have access to you may wish to skip this process and just create a new character on your already existing account.