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.
Bitcoin may be only expensive if only you want to invest what you can afford or you do not have a source of income. Bitcoin is an investment which everyone needs to cut his/her coat according to what they earn.
Bitcoin can be expensive if you are only thinking of buying all Bitcoin, but you don't need to stress yourself to do that. Bitcoin is not expensive and it is not only people who are earning well can invest in bitcoin. The most important thing when it comes to bitcoin investment is to have a source of income, with this you can be able to invest bitcoin with what you afford by using DCA method of investing. No amount is too small to invest in bitcoin with the DCA method so far as you are consistent with it. If you think bitcoin is so expensive you will end up investing in shitcoins which can land you into regret of waste of fund and time.