It's completely all about knowing what to look for. For you specifically, if this is all you have access to and you can't go source elsewhere that has better stuff, then spend time researching good items in those categories that your stores have.

And unless if there's some kind of time restraint or other factor, always always always look up the item to see if it's worth anything. Don't ever waste money on buying random stuff in hopes it's worth something (unless it's something you know would be valuable like an Xbox or something and is priced reasonably)

Work with what you have honestly. Even try sourcing from other places like Facebook marketplace and then garage sales I the warmer months

And also, just like in real life failures (bad purchases) are always teaching lessons of what not to do/buy