The first time we see the muffin kiosk, "muffins" is incorrectly spelled as "muffis". The next time we see the kiosk, the spelling is correct.
When Stan is purchasing his rocket boot, his large clock reads 2 o'clock, then later when he confronts Francine his clock reads 1 o'clock.
Stan couldn't afford the other boot because Francine bought the kiosk but Francine gave Stan his five grand back, there's no reason he couldn't have got the other boot.