Someone who lives a purposely sinful life has not likely been born again and so no, they are not going to heaven, not because they lived a purposely sinful life, but because they weren’t born again.
The sin we commit after we are saved does NOT affect our inheritance in heaven.
It does not cost us our salvation because we are saved by grace having been forgiven, not by works having performed.
Yes, we are saved by Grace and not works because there is no way any one could do enough to earn his way, a man might give his 12 year old son fifty cents or a dollar to fill the wood box, not that he earned it because that should be his job any way but if he don`t do it he won`t get the money.
Mathew 7
21 “Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but only the one who does the will of my Father who is in heaven. 22 Many will say to me on that day, ‘Lord, Lord, did we not prophesy in your name and in your name drive out demons and in your name perform many miracles?’ 23 Then I will tell them plainly, ‘I never knew you. Away from me, you evildoers!’
It appears to me that Jesus is speaking to a whole bunch of people who claim to believe in him and it is pretty plain they are going to hell.
The only ones who will enter heaven is the ones who does the fathers will.
James 2:14-26
14 What doth it profit, my brethren, though a man say he hath faith, and have not works? can faith save him?
15 If a brother or sister be naked, and destitute of daily food,
16 And one of you say unto them, Depart in peace, be ye warmed and filled; notwithstanding ye give them not those things which are needful to the body; what doth it profit?
The works James is talking about is what Jesus plainly told us to do.
And if we are doing what Jesus told us to do maybe we won`t have time to sin as much.