we love discovery united streaming. it is free in some states (mine included), but i also think it would be worth a subscription.
we have also paid for brainpopjr.com for K-2 ...or brainpop.com is excellent too...i just didn't pay for that when we used it...it's for grades 3 & up. anyway, it was worth the money imho.
lastly, we did pay for time 4 learning for about 6 months. it's $20 month, and although i wouldn't categorize it as a comprehensive curriculum, it was a lot of fun for my daughter. they give you access to the grade you register with, plus a grade below and above (so for my daughter, she could do anything in K,1, or 2). i thought that was pretty cool. we stopped using it simply because it wasn't our main curriculum & money was tight...so i cut it out.
there are many free resources on the web too. i've listed ones i like at my blog under fav. resources. it's a bit to sift through & it's not organized in the best manner.... i made the list to help me find things...*maybe* there will be something you like too? good luck

hth.
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