Keeping track of investments

For my company, all three partners plan to contribute a sum of money to the startup expenses. What is the best way to keep track of the investments made? I have been searching for low price accounting software for my company, and so far have found "ZipBooks" to be pretty nice. The reason for the picky search is that my company does not anticipate making any profits within the first operating year. We are piloting our software for free to a local high school, and will use the pilot for market research. We would all like to see a return on our investments at some point in the future, so I'd like to easily keep track of the investments so that we will know when they have been paid back. We cannot afford an accountant, so we must do all the accounting on our own.