Pay the card off in full or carry a balance monthly?

I have bad credit and by some miracle was preapproved for a card for bad credit. I applied and got approved. I have a 300 dollar limit. I did Max it out as I got a new place and money was tight. Bill came already and I was told many ways to pay it off. I was told by one person to pay in full, another said pay half off and the third person said pay the minimum balance. My check comes next week on the 4th and the Bill is due the 11th. I wanna pay it off but I got three different answers. Which is the best way to boost my credit?