When I started in GRC world, I did not invest any real money, but I found number of ways to increase my balance.
1. Join #gridcoin IRC and/or https://discord.me/page/gridcoin. Many members are tipping other people also on Discord there is faucet-bot.
2. Use faucets daily:
Account on eobot is very important. Not only a faucet is there (you need 100 GRC to withdraw), but also you can generate wallet addresses for other currencies. Then you use them to transfer money for example from other faucets and exchange them for GRC to get to 100 faster. You can get solid amounts of coins at Cointiply. Not only that, one of very few sites that you can 'mine' GRC and even 'mine' cloud computing to 'mine' even more GRC :).
3. Use free cloud computing money to run BOINC and increase your magnitude. I provide a link for Google, but there are other options (Amazon, Microsoft Azure) for doing this.