most of the "worms" are actually Larvae of a beetle or fly/moth so the chances are that they are unable to breed as "worms" although you can breed mealworms and superworms fairly easy, I have lots of little super and meal worms crawling around at the moment
Yep, always best to get advice from here instead of someone trying to sell you something.
you can buy crickets from www.livefoods.co.uk
for cheap enough
don't hesitate to PM me