ORD Blue Line +transfer=$5 or $5.25
The CTA website says if you buy a single use ticket at ORD, it is $5 including transfers.
The CTA website doesn't say if you use a Ventra card and transfer from the Blue Line to a bus, is the fare $5 or $5 plus 25 cents for a transfer.
Have you used a Ventra card (not single use ticket) from O'Hare and made a transfer to a bus?
I have a Ventra card that I use once in a while when in Chicago.