If you're interested in investing your money you have many options.  If you have a lot of "extra" money, it would be wise to work with a financial advisor.  A financial advisor will analyze your money and assets and suggest where your money would be put to the best use, either plunked down in one place or spread over a variety of investments.  One option of potentially low investment therefore attainable to many people is that of real estate investment.  

Doing a rehab on a house is very appealing to a lot of people.  The idea of taking a house, in one of the many different phases of condition, making the necessary repairs and giving it a makeover speaks to their creative side.  Many have tried and many have been burned because the proper research had not been done.  You first have to get the house for the right price, having already done good estimates of the costs to do the project of fixing it up.  First timers especially have a tendency to over spend here, making the sale price needed to recoup the total investment and make a profit too high.  Also appealing with the rehab is that once the house is ready and assuming you sell quickly, you stand to gain a lump sum at once.  The risk, assuming all your resources and efforts have been used wisely to this point, lies in the time it takes to sell the property.  Especially in a depressed market, which you can thank for allowing you to get such a great deal on the purchase of the house to begin with, it may take a long time to sell.  

The other option is investment property as a rental and become a landlord.  On one hand it would seem that this would be the less risky option because you are not at the mercy of the housing market and having to sell the house.  A slight risk is whether or not you will be able to find a renter, which if you have done your research and bought wisely in the right location, you should not have any trouble the renter.  The troubles of renting come into play screening the renters for someone who pays consistently and on time while respecting the property.  Even after the screening and interviewing you will probably occasionally not receive your rent on time and you will have to track the tenant and the money down.  You have already thought about maintenance on the property, but have you considered late night emergency repair calls?

The interest in owning real estate is a growing trend.  Whether you are considering buying a house to rent out or buy one to fix up and sell, the practice can be very profitable.  Notice I said, "can".  It isn't guaranteed.  As with anything, do your research and make sure your expectations are right.  It will take work to build wealth with investment properties.