what is the lowest bitcoin at the moment?
go to a website that is reporting the price like
http://preev.com and see what the price is at any moment!
if you want the lowest price to buy bitcoin at, then it depends on where you go to buy and what method you choose to buy. exchanges usually have the same price more or less in similar currencies, for example price is nearly the same in USD but in other currencies like INR it may be different and much higher (it reached to 40% higher than USD value!).
as for method using p2p methods usually costs more.
whether to return to the price as early as 2017?
nobody can tell for sure, but since nothing about bitcoin has changed and the adoption for it is still ongoing I'd say it will be at $20k and then rise even more beyond that eventually.