I was playing some Smash Brothers the other night and found that I needed to earn 5,000 coins in coin battles to get an achievement. So I went about testing to see the easiest way to do so.
First I set it to my favorite custom stage which is nothing but a small enclosed pit with conveyor belts continually dumping everything into it. I normally use this for collecting sandbags but it works perfectly for coins as well. Any coins that land on the ground will be pushed right onto you. Now you want to pick Bowser because he is HUGE. Set 3 computers to lv 1 and make them all Captain Olimar (because he's really short). Set the match to about 5 minutes time (this is about long enough to get a couple thousand coins) and turn on max metal boxes. I left max sandbags as well so I would earn CDs and stickers at the same time.
Head to the middle as soon as you begin. Just keep repeatedly up-smashing and you will bounce up and down, damaging the little guys who will keep getting dumped on top of you. You will continuously knock coins out of the computer players and stickers from the sandbags. Because you are so much taller than the computers, almost all the coins will be dumped right onto you and you will get credit for it. I did about 2 rounds of this and got my 5,000 coins achievement. This will also work great for earning lots of stickers and CDs from the sandbags.
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