Whatever you sow you shall reap. If you sow knowledge in the heart of people more knowledge is given to you as reward. If you sow foods, you reap more foods. If what you sow is financial, you reap more.
The kind of giving that works best is the kind you do free of charge, or without expecting to be rewarded by people. You get real reward from our CREATOR, in great measure. This is why it's recommended to give freely and anonymously, because if you give to be seen, you are likely doing it for reward from people in whatever way. This typical void the real reward that comes from the CREATOR.
Giving freely is like an investment, you either invest to reap the reward from your consumer or from your CREATOR. The reward that comes from the CREATOR doesn't necessarily come through your consumers, it could come from breakthrough in your life, from being more favored or blessed in things you seek to achieved.