I do not recommend picking a ready made curriculum with all subjects included. I like to pick things in pieces. This for math, that for science, this for reading, that for spelling, this for history, that for writing and grammar, this for religion, that for handwriting, this for art, that for music, etc. I think it is cheaper and more tailor-fitted to you and your kids that way!
In addition, keep in mind that if you have a budget, you need to save $200 for the awesome back to school sales in July and August. I go shopping every week in those months, just for what things are on sale that week at these stores. I have to stock up for a big family, for the whole year. I do not have the luxury of having the public school provide any supplies.
If I were you, I would also plan a way to get some money for education into your monthly budget, because things will come up, year round (field trip opportunities, group events, etc.). Do not be overwhelmed by all the stuff you need, because if you make a list, it will be longer than what you can afford. Just keep in mind, that this year, you may use all the money for these, and next year, you will use all your money for those, and the next year, you will finally be able to afford this and that.
I was talking to a mom who had done it for 20 years, and it sounded like she needed nothing. She had accumulated it all, but she had been at it 20 years. You have to keep that in mind. When I started, for the first few months, all I could afford were paper packs and pencils. We did fine. Slowly and gradually, I got more and more of what was needed. I have been at it 2 and a half years and home teach 5 kids.
We just got an iPad a month ago. I love it, but do not get that as your first item. Get the basic stuff first. Make a list of all that you want or could dream of. Then put it in order of priority. Get the things at the top, first. I say, first, you need lots of school supplies, reading books, spelling workbooks, math workbooks, lots of little, separate science and history fun to read books, bookshelf, 6 ft. Tall closing cabinet, bins and plastic organizers, a wall calendar, and a white board. In the school supplies category, I recommend you get plenty of printer paper and ink, for all the stuff you will print from the web, Manila folders, staplers, pencils, pencil sharpeners, calculator, erasers, paper clips, brads, glue sticks, crayons, colored pencils, markers, scissors, watercolor sets, play dough, etc.
I have no idea what age or ages of kids you have. If your child is a high schooler, you will not need play dough, but maybe a chemistry set. I recommend the homeschool mom day planner from http://www.Mardel.com, only $20 including shipping!