Lagniappe

n.	1.	In Louisiana, a trifling present given to customers by tradesmen; a gratuity. Lagniappe . . .is something thrown in, gratis, for good measure. - Mark Twain.
	2.	A tip or gratuity.
	3.	Anything obtained gratuitously or unexpectedly.

Noun

1.

lagniappe - a small gift (especially one given by a merchant to a customer who makes a purchase)

Trinkgeld, balance, bonus, bonus system, bounty, bribe, consideration, decoration, dividend, donative, double time, extra, extra added attraction, extra dash, fee, filigree, filling, fillip, flourish, frill, fringe benefit, gratuity, gravy, grease, honorarium, incentive pay, inducement, largess, leftover, liberality, margin, ornament, overage, overmeasure, overplus, overrun, overset, overstock, oversupply, overtime pay, padding, palm, palm oil, perks, perquisite, perquisites, plus, pourboire, premium, remainder, salve, solatium, something extra, spare, sportula, stuffing, superaddition, surplus, surplusage, sweetener, tip, trimming, twist, wrinkle