I'd get a moveable alphabet, a simple base ten set, and borrow lots of books from the library. That will cost you less than $100.
If you want to get fancy, a simple balance and gram weights, a tape measure, and a clock might be fun for her to play with.
Singapore Math books are wonderfully inexpensive, I understand, and pretty consistently appreciated around here.
You might want to look through some regulars' back-posts. Off the top of my head, these folks have home-schooled (and/or virtual schooled), or are doing so now: HowlerKarma, Portia, doubtfulguest, madoosa, Lovemydd, MK13, and amazedmom. Lovemydd made a terrific post about a year ago detailing all the materials in her home school that she designed for her daughter, who was about your daughter's age at the time.
My son has loved Starfall, and he also has a spelling app that he adores. I'll look up its name and get back to you. The cost is about $3 for each of those.
