corsa judders when i pull off i first?

Whenever i pull off in first gear my L reg corsa judders like the engine is about to stall, also when i reverse it judders. I have no other problem in the other gears just theese 2!
what could the problem be? and how much will it cost to fix? i am a single mum with 2 jobs on low income and i dont want to get ripped off!!
Many thanks