The answer is that '''I want a Spiderman toy from a blind box set'' is the opposite of samma sankappa (aspiration towards renunciation and good will) https://www.accesstoinsight.org/tipitaka/sn/sn45/sn45.008.than.html so you are not on the path and create karma once you act on this will, (creating karma is always the opposite of the path, even creating good karma), which in your post is speculating about how to get the right box, then later on executing your plan which is peeking, then choosing the box.
The way to respect the precept is not to compare each one of your activities with the precepts and then speculate whether or not your actions comply with them, in order to determine whether or not you are a good person. If you compare your actions with the precepts, it just means you are already on the verge of breaking the precepts.
The precepts are here to be an explicit border for your actions. If you wonder or not your actions break a precepts, like precept of taking what is not given, then it just means you do not understand samma ditthi nor samma sankappa, which is normal for any puthujjana, especially a puthujjana who does not get the citta into samma samadhi.
THe way to respect the precepts is to first track and judge your thoughts and vedanna+sanna, to judge whether the thoughts and vedanna are meritorious or not (for most puthujjanas, the vedanas, sannas and thougths experienced are demeritorious), to judge whether they lead to affliction to somebody, and then to strive to execute only good thoughts.
This way, you are guaranteed to never ever break a precept. The next step is to ''incline the citta towards renunciation'' by seeing the danger in lust for sensuality and ill-will https://www.accesstoinsight.org/tipitaka/an/an09/an09.041.than.html. At this point you get samma samadhi and you can make merit (respecting the precept and avoiding bad thoughts is more about avoiding demeritorious actions than generating merit) since well the samma samadhi is the way to get ''desirable contact'', meaning meritorious vedana, sanna and creating good karma.
THis is what the buddha explains here https://www.accesstoinsight.org/tipitaka/mn/mn.019.than.html
Once you want to stop making karma, you really need to destroy the sankharas, so even abiding in the jhanas as a puthujjana is not enough. of course, in theory getting samma smadhi from samma ditthi already does not rely on sankharas, therefore only generates ''kamma that is neither dark nor bright with neither dark nor bright result, leading to the ending of kamma.'', from here https://www.accesstoinsight.org/tipitaka/an/an04/an04.235.than.html, but in practice puthujjanas always rely on sankharas, especially at the beginning, because they have to force themsleves to follow only the good thoughts.
in one sutta, the proper behavior is here https://www.accesstoinsight.org/tipitaka/an/an05/an05.200.than.html https://www.dhammatalks.org/suttas/SN/SN45_2.html