That's sort of a question with no answer.
How much
would I spend on a card?
For the right card? And with unlimited budget? Who knows?
The more important questions are
How much
could I spend on a card?
That's variable, and a much smaller number than I'd like.
Or
How much would/could I spend on any particular card.
Which is even more variable.
I also happen to be more than a bit cheap at times. Currently I'm wrestling with vg common T206s being almost 100. When I started that would have got me a Goudey Ruth. OR 10 T206 Hofers.
