David wrote

My view of expensive was set some decades ago so I have to think around
it.

You can spend an awful lot of time on line trying to find a
slightly cheaper item, and comparing prices and specifications.
There must be a point where it isn't really worth spending the effort.

My rough limits a

£9.95 for almost any small item. Sod it, just buy.

£25 for a slightly more substantial item.

£50 for a more substantial item (e.g. cheapish charcoal BBQ).

After that I struggle, but I tend to use the current
price of a supermarket shop for comparison.

For example, if I am happy to shell out £100 for a week's food including
a bottle or two of wine and a bulk purchase (say a 6 pack of tinned
tomatoes) then in the great scheme of things any other purchase
in this range isn't worth costing as a once in a lifetime purchase.
I suppose £99.99 is another break point for tools and stuff.

I dont work on dollar numbers, too logical for that.

Not that I get to spend a lot out shopping at the moment.

I'm pricing up bed risers (dodgy knees) and wondering
if I should go for the £25 or £36 option.
Meal for two prices?
(As far as I can remember.)

Anyway does anyone else have a yard stick for measuring
time and effort put into research against the cost of an item?

I'm not convinced that there is one.

And to muddy the argument even more, I now realise
that I will never spend my vast accumulated wealth
before I die, so it makes sense to buy whatever makes
my life more convenient and enjoyable.