It is your station's decision whether you want to accept it or not. You are required to track all requests received by polticial candidates for airtime in your poltical file, even if you turn down their request. If you do grant the airtime and you charge them for the airtime, you must disclose in the political file how much they paid. Political file data must be retained for at least two years. Your political file is a part of your station record and must be presented if requested during an inspection. LPFM (and other non commercial stations) are prohibited from endorsing poltical candidates per section 399 of the Communications Act. Endorsements may also violate state and IRS regulations. REC's advice is for LPFMs to always steer clear of politics.