Investing in Bitcoin may not be expensive for those who have money but Bitcoin is very expensive for those who don't have money. But it is wise to invest even if the cost is high because if you want to invest in Bitcoin you have to buy a few digits and in this case you don't have to invest in a Bitcoin because whoever has the ability will invest in Bitcoin according to that ability.
If you are talking about buying a whole coin, then even if the price of a whole coin sits down on $1k then it wont really be that still affordable for most people. How much more into those prices on which we are sitting now @67 or 72k prices? If you would really be trying out to invest or buy a whole coin and if you do have that money or you could simply afford then you could purchase it out but if not then we do know that we can buy Bitcoin in fractions on which it isnt really needed for you to buy a whole coin. If you do really believe that Bitcoin could give out that opportunity to make profits in the future then you could buy in small parts.
It wouldnt really be that expensive since it will really be just that basing up into your financial capacity or budget into that particular point. The key on here is that you shouldnt really be that making yourself that get stressed on the moment that you do make out some invesment, plus invest on the amount on what you can afford to lose and never ever consider on going all in.