1. A computer-implemented method for providing cost-per-acquisition (CPA)-based online advertising, comprising: receiving a set CPA pricing for a designated action, the set CPA pricing including a targeted conversion rate, and the targeted conversion rate including a ratio of an expected number of conversions to a number of clicks of an on-line advertisement; computing and dynamically updating a cost-per-click (CPC) value of the advertisement for an advertisement traffic source based on at least one of a price variable, an advertisement traffic source variable, and an advertiser variable; dynamically determining a ranking of the advertisement based upon the updated cost-per-click (CPC) value and the set CPA pricing; automatically uploading and distributing the advertisement to the advertisement traffic source based on the dynamic ranking; and determining an advertising placement within the advertisement traffic source based upon the dynamic ranking, the at least one price variable, advertisement traffic source variable, and advertiser variable, and the designated action; dynamically determining a conversion rate of the dynamically updated cost-per-click (CPC) and the designated action; dynamically updating the cost-per-click (CPC) value of the advertisement for the advertisement traffic source based on a ratio of an expected number of conversions to a number of clicks; and dynamically raising the cost-per-click (CPC) value of the advertisement when the ratio is above a targeted conversion rate and dynamically lowering the cost-per-click (CPC) value of the advertisement when the ratio is below the targeted conversion rate.