In World 1, you can get tons and tons of coins to make you have a life!
For World 1, level 3, beat the thingie in the front by stomping and kicking the turtle shell at it. Then kill the turtle on the top of the brown thing and kick it into the big area so you can go into it. Jump up a little, right next to the long line. A white/red jump block should appear where you can jump up REALLY high and get around 30-40-50 coins.
For World 1, level five, kill all those little blue things and go UP, take the up path, don't go where the water is. Just keep jumping up and down until you see a white/red jump block. Jump on it, and you will recieve tons of ulimited gold coins.
If you get both of these, you will earn an extra life.