PSA 1 prices will vary more than any other grade, because a PSA 1 could mean a totally smashed card that has minimal eye appeal, but also could mean a card which presents nicely but may have some paper loss on the back.
For a smashed 1 like
this one, you will be closer to $750, but a nicer 1 like
this one will put you at least at $1500, and likely higher than that.
Scott