The Torah says that one must pay a worker by nightfall. Does that apply when one purchases something? For example, if one orders a cake and doesn’t pay on time, is there a Torah law that is violated(of course if one eventually pays as otherwise that would be stealing).
The mitzva of paying workers on time only applies to a service that is provided by the worker, or money being paid for a rental. It does not, however, apply to purchases. Therefore, although you should pay for the cake promptly, this mitzva will not apply to it.
Babba Metzia 112a.