Weight loss

Hey guys.  I have been wanting to lose weight for years now. And everytime I try, I can lose about 5 lbs and then I gain it right back. Cutting calories just doesn't seem to work that well for me.
And a lot of exercises I can't do, because i have bad arthritis in my knees, so some of the leg exercises i want to do, hurt too bad.  And sometimes I wanna push through the pain, but I've read, that its not a great idea.  I could injure them further.
I also read it's best to make yourself SMALL weight loss goals, so you don't try so hard and when you don't reach your goal, you give up.  So I made my goal 5 lbs in a month. Which I know is do-able.  I just need help getting there.

I 'm going to try to cut back on calories (but that will be hard, since I don't have a job and my roommate does all the grocery shopping and cooking. And she has NO desire whatsoever to eat healthy) and doing some exercises.
So I'm asking if you have any good ideas for dropping a few pounds in a month please let me know!!!!!!
And don't forget I can't BUY anything right now. I don't have any money. (it really sucks. ... hopefully I'll get the job I interviewed for the other day)
And if you could please remember that bending my knees causes extreme pain, so try to find other exercises to do instead.


Really, I know most of us are trying to lose weight. Some of us really need some help!!!!!! So if you can help, please do.