Do some work and research the freemium model and you'll see that it is possible. Depending on the nature of your product, you may want to checkout dropbox & Eve

Do some work and research the freemium model and you'll see that it is possible. Depending on the nature of your product, you may want to checkout dropbox & Evernote. Both are great examples of different strategies that help convert free to paid users. Generally speaking, a 5% paid to 95% paid to free ratio is really good. Good Luck.