JTF sell cheap plastic tat, its only a mile from me and takes and hour to join and then you have to sign in and get marketing crap sent very fortnight, its full of the great unwashed, ladies with blotchy red legs, pikeys and doley scum that look into your van just to closely. So tend to give it a wide berth.
Personally don't think it worth shopping around for consumables as they are such a small part of the job the savings are minimal overall. by the time you factor in time lost and diesel they don't work out that cheap.