Well to be honest I never thought it would drop this low. I have been buying ever since 140K satoshis, so the dip down to 80-ishK satoshi's is an absolute steal IMO. But nobody knows for sure, Segwit2x is still two weeks off. It may go lower. I was very tempted to buy more today but it jumped back up before I could.
In dollars I'd say anything below $6.80 is a pretty good price, lower is better obviously.