There are several ways that you can earn donation credit and site rewards without actually donating anything. Detailed below are a few things you can do and their corresponding benefits.

Refer a Friend
Get a friend to join the RPG, mention that you referred him or her in their join form, and then if they remain active for 10 updates, you will receive $5 in donation credit, and then both you and they will receive +100 all stats, + 500 zeni, and +10 DP.

Sign up for Robinhood
Sign up for the Robinhood stock trading app using my referral link: https://join.robinhood.com/alexh1102 and then complete the sign up process (it's a legit brokerage so you will need to use real information but it is completely safe - Google more about it if you are concerned). You don't have to spend any money on this for the referral to count. Not only will you get a free stock yourself for using my referral link (Chaos got a free share of Microsoft worth approximately $185 at the time of this writing - ask him!) but you will also receive $10 in donation credit, +500 all stats, +500 zeni, and +25 DP.

Sign up for Worthy Bonds
Sign up for the Robinhood stock trading app using my referral link: https://worthybonds.com/?r=EuBvO and then complete the sign up process. Worthy Bonds loans money out to small businesses and sells you $10 bonds that accrue 5% compound interest automatically each year. The bonds can be cashed out any time and interest accrues daily so you can even cash out interest before the bond matures. Signing up will earn you a free $10 Worthy Bond for yourself, and you will also get $10 in donation credit, +500 all stats, +500 zeni, and +10 DP.