Damn it, Tumblr.
The first shop they reach is rather empty. Of course Remus doesn't let himself be lulled into a false sense of security.
He's searching, hoping, almost praying that Black Friday will not become Sirius Black's Friday. Any day with Sirius is a day destined for insanity, but Sirius Black's Friday will inevitably end in pain. Or arson. Murder, even, because if there's one thing worse than determined Sirius Black, it's bargain-shopping Sirius Black. For a rich boy, Sirius can as sure as hellhunt. Maybe it's the dog in him, sniffing out good deals and adorable fashions for reasonably low prices.
The first shop is empty for a reason, apparently. Browsing the wares, dusty old volumes and tomes that are well past overpriced, not even Remus can find something of value. Sirus almost has to drag Remus away from the shopkeep, a very English, rather pudgy, and gayer-than-a-maypole man with a slightly formidable companion dressed in dark colours, because, well… the bastard wouldn't let him buy any books!
Still, Remus is a gentleman and leaves peacefully. (Even if he wants to snarl and sit among the books for hours.) The last words be hears before apparating are the shopkeep's companion exclaiming, "Angel," in an awed manner.
The next shop they arrive at is much more lively, if by 'lively' you mean 'stark-ravingly mad.' It seems to be a muggle apothecary, although Remus can't fathom why muggles would even need an apothecary. For starters, as soon as Remus and Sirius enter, Sirius goes off running. Remus contemplates whether to give chase or to wait by the door, but someone catches his eye. It's a small blonde man, rather short but slightly tanned. He leans heavily on his right leg, arms crossed over his chest. "Damn it, Sherlock," Remus hears him mutter. "The one time you'll come to the shoppes with me and you run off."
Remus is glad to see he's not the only one in this situation. He stands for five minutes before there's a commotion from the back. Remus takes off running in the direction of the disturbance. "He just collapsed! I swear," comes Sirius' voice from ahead. Remus arrives to the scene; a large, curly-haired man in a coat and scarf lies on the floor. "Sherlock," comes a voice from behind him, and the blonde man appears ahead of him. Remus takes the opportunity of distraction to grab Sirius' arm and drag him away, despite his ever-growing struggles.
They reach the mens' restroom and enter.
"What the bloody Hell was that about, Remus?!"
"You can't just stun a muggle, Sirius! What the hell could he have possibly done to you," Remus asks fervently.
"Sage," Sirius mutters, eyes downcast.
"What?"
"There was an entire bundle of uncrushed sage just waiting for me, Remus!"
Remus sighs, grabs Sirius, and apparates to their apartment.