Rake leaves, mow lawns, shovel snow. If you can play an instrument or sing, stand on a streetcorner with your hat out. If you're artistic, sell paintings or crafts at a fair or online. Clean out your closet and sell things you don't want anymore on ebay or storenvy.com. Babysit. If you live with your parents, ask them if there's anything extra you can do around the house for a few bucks. Make origami paper stars and sell them on garlands or in jars. Walk dogs. Repurpose chairs from yard sales or street corners into cute deco pieces and sell them. There's tons of stuff you can do.
There are a lot of online jobs that you can try to consider if you are good at something. You can also get a loan from http://www.quickloantoday.us Since it is only for a concert, you don't need a huge amount.