@Mary5689 What country are you from?
In the US nearly all funeral homes offer what is called a "Funeral Trust". This is essentially a bank account that will release the money to the funeral home to carryout the final disposition of your remains after your passing.
Besides the peace of mind this offers, it also locks in most of the pricing, so your dobt have to worry much about inflation.
I set this up for myself, and I'll have a direct cremation when the time comes. This cost me $2,350. (NYC Area pricing).
Some funeral homes also have payment plans where you can pay a little at a time and still lock in the pricing.