The agency, which was launched in June this year as a digital resource for Elvis, Cossette's direct marketing business, picked up the account following a final shoot-out against WCRS.
Spike will create TV, press and poster campaigns as well as online advertising for the site, which has been designed as a competitor to sites such as gocompare.com and confused.com.
As the brief develops, the agency will be helped by Cossette stablemates Elvis and Miles Calcraft Briginshaw Duffy, which already works for the rival price comparison site uswitch.com.
Earlier this week, Which? released a report, Food Fables - The Second Sitting, that claimed food companies have switched their marketing efforts from targeting young children to teens, using devices such as social networking and text messaging.
However, ISBA has hit out at the report saying that it "misses the point" and that where obesity is concerned, advertising is not the issue. It said that tackling the problem among the young requires wider ranging initiatives.
The body also criticised the report for attacking advertising practices that are not aimed at young teens, but at over-16s.