The demonstration was organised by the Time 4 Change group and marched through the city and past St James' Park ahead of Saturday's Premier League clash with Liverpool.
Ashley has courted controversy throughout his ownership of the Magpies - most recently with the sponsorship deal with Wonga and the appointment of Joe Kinnear as director of football.
Kinnear said in his programme notes: "The chasm that exists between the league's six most commercially powerful clubs and the rest is significant and growing ever wider.
"Even putting the strongest four performers to one side, clubs like ours really have to over-perform in all areas in order to compete season after season with the likes of Liverpool and Spurs.
"Their last published accounts show turnovers of £169m and £144m respectively, compared with our £93m. While that gap is striking enough, it is in respect of commercial turnover where the real gulf is evident.
"Liverpool reported a commercial turnover for 2011-12 of £64m while Spurs reported £53m. Ours, in contrast, was just shy of £14m, increasing to £17m for 2012-13.
"We cannot, at this time, compete commercially with the very biggest global brands in football because the hugely lucrative (sponsorship) deals will go their way. But what remains of the marketplace for the rest of us, we must and will fight for our share, and more.
"Through astute financial management and by maximising every commercial opportunity available to us, we will give ourselves the best possible chance of competing on the field with those whose strength off it makes them - on paper at least - untouchable."