No candidate or candidate's authorized committee is allowed to transfer campaign funds (or items or services purchased with campaign funds) to any other candidate or political committee, unless a candidate is legally transferring surplus funds to a bona fide political party or a caucus political committee.

A candidate may reimburse another candidate or committee for his or her share of a documented and properly reported joint fund raising campaign expense.  A candidate's campaign may also buy campaign-related goods and services from another candidate or political committee so long as the campaign pays the fair market value.

RCW 42.17A.430