A great answer by Lenny. Should you care to look up the law that talks about licensure in MN, you can find it at the following webpage.
If you do plan on conducting more than 5 real estate transactions for yourself in a 12 month period, you can obtain what is called a Limited Broker's License. The reason it is required is found in statute 82.55 subdivision 19, paragraph G.
Good Luck in your endeavors!!
Coldwell Banker Burnet
Licensed MN Real Estate Broker