You can change your user name by accessing the "User CP" User control panel and from the links on the left hand side under 'Your Profile' click on the link that reads 'Change Username'.
In regards to your original question as LakeRat suggested it would depend a lot on the software and even the CMS you are planning on using, however most customers start out with our shared hosting plan and upgrade as their site grows.
'Shared' hosting plan is the most affordable and includes everything you need to host your websites. You get unlimited domain hosting, storage & bandwidth, and email accounts.
Our one year prepayment is $119.40 ($9.95/month) includes the 1st year of domain name registration for free. You can also pay month-to-month for $10.95.