I'm pretty sure that Krista has a workout you can do with household items here ... www.stumptuous.com
My daughter does squats with a backpack with books in.
Definitely get a ball! You can do all kinds of things on it, and it strengthens your core like you wouldn't believe. As you can afford it, pick up dumbbells and resistance bands. There are lots of sites on the web to give you exercises using these items.
I think getting a good video is great for someone just starting out so that you can check out correct form. Collage vid has a lot og great videos and you can search buy how advance you are. Beachbody also has a lot of great programs that use dumbells or bands like Slim in 6, Power 90 and Project You.