I don't know much about cellphone plans,, but i do know that 300 Mins wont last you a month carl,,, unless you do most of your talking at night (after 8) it's good to have for $29.99 and the Nokia 3390 is a very nice phone (mom has one) but i would go with the 600 mins,, or even more ,, it's worth it, cause if ya go over , you wont be happy at the end of the month
If you are afraid of going over your anytime mins limit,, do what i do,, get a 'pre-paid' account, the phone IS NOT free this way, but it's alot cheaper in the long run (you can buy $10 all the way to $100 minute cards ,, and they last you a month and cost less,,, and there is no $300. Bill if you go over,, cause ya have a limit,, and if ya run out ,,, just go to a local place that sells 'em and put it in,,, VERY EASY done ,, even i can do it
just my opinon ,, and if your looking for a good pre-paid Provider,,, AT&T is one of the best , T-moble (VoiceStream) is right up there as well

Make sure you buy a case to put the phone in!!
,, salt air and atmospere is not good for them phones,, ask StarsnStripers, a LONG day on the water disabled the keypad
good luck!