Support is significantly higher with the $1.9 trillion price tag attached (58%) than with it omitted (51%), with the difference coming entirely from those who are not sure. Opposition is exactly the same (25%) for both versions of the question.
Perhaps the result was a random fluke, with the more supportive half sample hearing being more pro-Biden or pro-Democrat? No. By chance, the respondents who saw the price tag were slightly more Democratic in their party ID (42% Democrat, 31% Republican, with leaners included) than those do did not (41% Democrat, 34% Republican), but the difference was statistically insignificant and considerably smaller than the gap in support for the relief package.
More importantly, the gap was present across the party spectrum. Support for the relief package was eight percentage points higher when informed of the $1.9 trillion price tag among both Democrats (88% vs. 80%) and Republicans (29% vs. 21%).