as others mentioned the seeds you can buy at walmart are
A. almost certainly aren’t the type of poppies that contain opiates. there’s a variety of poppy plants, the majority of which contain no psychoactive chemicals, at least not to any significant degree. there’s like a 100 types of poppy (Papaver) flowers, and the specific species that contain opiates are Papaver somniferum. the seeds themselves are legal and sold some places but aren’t sold outright at walmart. so while walmart does sell poppy seeds, it’s not the opiate kind
B. most seeds of the Papaver somniferum that are sold are washed, meaning the seeds have been washed to remove any traces of the opiates that come from the plants. the seeds themselves don’t contain any opiates as is, and when washed it removes all the residual alkaloids that could be left on the seeds from the growing process. so theoretically even if you did get your hands on the right seeds, you would have to grow the plants which would then take multiple months to grow before producing any psychoactive alkaloids. most sources of Papaver somniferum seeds sell washed seeds for legal and liability reasons, so the seeds you could get at walmart, even if the right species, would 100% be washed and need to grow to contain any opiates
C. like others have said, making poppy tea (from the dried seed pods produced after growing the plant (which unlike the seeds you cannot legally buy in the US) or from unwashed seeds) like that can be incredibly dangerous due to the inability to accurately dose the amount of opioids you’re getting. i’ve done lots of unsafe ways to get high but making tea like that is literally just rolling the dice with your life.
TL;DR- the poppy seeds at walmart aren’t opium poppy seeds, and even if they are you can’t get high off the seeds because any seeds that are sold at walmart (and the vast majority of sources of opium poppy seeds) would be washed, which removes any residual alkaloids and the seeds themselves don’t contain any opiates
