the suggested CPC is a function of your targeting and mainly your ad CTR. the lower the adCTR is, the more you will pay for each click as FB (and no one for that matter) does not "sell clicks" but "sells ad impressions." get your adCTR up, the CPC will go down and vice versa. also, the smaller your target is, the higher the ad frequency (no frequency cap settings at FB) will become, lowering your adCTR and hence increasing the min bids.