The direct debit payment plan makes it very affordable and the team's form and the quality managerial set up will also prove attractive to these people.
The club would be fools not to make a BIG thing of this in their press / billboard(/whatever) advertising they put out to entice newbies into the fold.
A picture of a father and son, looking all glowingly happy and middle-class, bedecked in blue and white scarves, cheering (another) Murray goal at the Amex from a seat with a spectacular view accompanied by a tag line of something like "Make sure you don't miss a single Albion goal at their new home next season. Father and son season tickets from only £35 per month" (or whatever the minimum DD is).