Have reacurring sciatica?

I have reacurring bouts of sciatica,I do get physiotherapy,but often feel bouts coming on and physio is $$,any tips for home excersize?I have mobilty issues(walk with walker),stroke survivor,but have a balance ball,mat etc..any help would benefit!

Hippychick has the right idea...one must first identify the cause of the sciatica...which yes, is usually disc displacement. The exercise she described is known as repeated extension in lying...one commonly used exercise in physical therapy. However, it is imperitive to know that if this maneuver causes pain to increase and it reamains increased even after you stop performing the maneuver, or if it causes your symptoms to radiate where they didn't radiate before, then this is not the appropriate maneuver for you. In this case, one would require some modification or different direction of movement.

Follow up with a PT, and check out Robin McKenzie's book "Treat your own back" which is frequently used in a course of PT.

Do you know the cause of your sciatica? The most common is a bulging/herniated disc I think . . . Please - don't do ANY exercises without clearing it first with your doc or PT who is familiar with your condition. But . . . I have a herniated disc in my lumbar spine that has given me sciatica. The exercise my PT gave me to do is:
lay on your stomach, with your arms at your sides and hands down at about chest level (your elbows will be bent up in the air). Then, push the upper half of your body up with your arms while leaving the lower part of your body on the floor/mat. If you're familiar with yoga, this is almost identical to the "cobra" pose. Do this a few times and it should help get things back in place.
BUT - that is for a lumbar disc herniation - if your problem is different or even just in a different area of your back (like thorasic) CHECK before you do anything because you don't want to make it worse.
Also - avoid bending forward and if you have to, counter it by bending back (by doing one of these exercises or stretching on the floor - don't fall down ;-)
Yoga is also great - you can get pretty low cost dvd's or tapes to do at home - but again - make sure you're clear for doing that kind of thing and choose the right level of exercise so it's not too hard on you.
another thing - if you can get out - check your local Y for yoga or other classes. The Y I go to has some tailored especially for adults with mobility problems - and it's also pretty low cost, any Y will also offer financial aid.