With the online program, you can only file one return per account, and each return will incur separate fees.  

With the program installed on your desktop computer, you can prepare an unlimited number of returns for personal use (self, family). The first 5 can be e-filed, the rest will have to be printed and mailed, this is an IRS limitation.  Federal e-filing is free, state e-filing is $20 or $25 per return.  Each state preparation module is about $40, although most copies of the program include 1 state free.