Hello Joel - thanks for reaching out. There are a couple opportunities to financially contribute to a campaign. The first is to promote the petition, which helps raise it's profile on Change.org.
Here is a link with more information about promoting petitions: http://help.change.org/hc/en-us/articles/217103508.
We also have the option for petition starters to create fundraisers around their petitions. Fundraisers allow users to collect financial assistance for a stated goal. Here is a link with more information about Fundraisers on Change.org
If you feel that a fundraiser looks suspicious or the intended use of the funds is too vague, please do not contribute. I hope this information helps! Please reach out to us at help.change.org
if we can be of any additional assistance. Thanks! Zo