Been looking for this forever. Here's what I recommend - coinmarketcap.com has coins and http://coinmarketcap.northpole.ro/api/usd/all.json does a update of these. Yet, it's not what you're looking for because it's a program and doesn't store squat. 

What I've been doing is literally pulling it out of coinmarketcap. But, unfortunately, I'm not consistent. It's a shame that none of the bright minds here (I'm not a programmer) doesn't create a program off coinmarketcap to store the data. So much could be done in terms of analysis. With the little data this year I've pulled I've learned so much about what causes price alterations in these coins via panel regression.