I have xbee pro s3b but XCTU doesnt see xbee. What board ı must use ?
I would suggest using an XBIB-U-DEV interface board.
Any luck with a more affordable board option?
That depends on the board and what firmware is installed. Most 3rd party boards don’t connect the required lines for programming or connect lines that are used for different functions with the XSC code loaded on them. What I would suggest is looking at he manual for the 900 HP/XSC. Then look at the schematics for the boards you are considering. As long as the required lines are there and the reset line or config line are not connected, you should be ok.