What is the lowest broker fee possible?

Also from the UniWiki on Trading:

Standings

Faction and corporation standings relevant to the station the orders are placed in will have an effect on the broker fee. Faction standings contribute significantly more than corp standings. The exact formula is:

BrokerFee % = (1% – 0.05% × BrokerRelationsSkillLevel) / e ^ (0.1 × FactionStanding + 0.04 × CorporationStanding)

(A picture is also available, but it is a tad confusing)

With 10 faction and corp standing, the broker fee is reduced to 0.185%, saving you more than 1% through the buy and sell process.