[gnfargbl]

"TBs scanned" is the number of tebibytes of stored data that the system had to scan to serve your query. This is how BQ is billed, in the on-demand model.

The console shows you this number (in very small letters) after you have entered the query but before you press go. In the on-demand billing model, which is what you were using, you can multiply this number by $6.25 to understand your query cost, exactly.

It's a design that's hostile to new customers, I agree. But it is comprehensible.

[gpvos]

There should be a cost estimate displayed prominently by default, and an option to turn it off for power users who know what they're doing (but keep the current less-prominently displayed amount of data estimate).