Bartering on flea market ran me over

I believed once it said how much of a given item the seller had in stock is what I would receive upon trading in my item.

I saw a trader who had 6 GPU for 6 Intelligence papers.
I bought the barter and received 1 GPU for 6 intelligence papers.

So I got wrecked big time. I’m not rich by any means I just get by in this game, and really enjoy it. But this here was just taking a ballistic missile to the spleen. I really think the bartering function could be reworked. As in before the barter is final a window will appear and say “you give xxx amount of xxx and receive xxx amount of xxx. Do you agree to these terms of the barter?”
I looked over the bartering again today and I see other people who has 149 GPU in stock and will barter for 1 LABS Black keycard.
I fully understand how someone else whom is not custom to bartering on the flea could believe he would receive 149 GPU. But evidently only end up receiving 1 out of the 149.

Am I the only one who fell for it?