Hi Rachel, Yoga can be expenssive but it's brilliant! Maybe try a class - lots of recreation/leisure centres have beginner classes that aren't so pricey, and if you feel it's worth the investment carry on going, or if you're worried about the cash try a yoga workout DVD. Speaking of which there are loads of brilliant workout DVDs - all of Davina McCall's are great, Kettlersize is really good for toning, 10 minute solutions are fab and Jillian Michaels gets results!
Good luck - and keep us posted.
Laura x