Samsung SCH-A570

I've seen a bunch of responses about a DUN #777 and it allows internet access, but how , is it free , how much does it cost , I use to have a Sanyo MM-5600 but lost it at the mall along with my purse , Sprint sent me a Samsung A800 because the Sanyo was out of stock , let me just say that this phone is amazing , its so cute and pretty and sexy , but enough about me...Just Kidding ! But if anyone can teach me or help me in my predicament I would greatly appriciate it considering everyone here on this website is very educated in cellular phones and services. Thanks in advanced.

Sailor Moon