Employees at Electric Fetus record shop in Minneapolis said the musician did not look “in the best shape” when he visited the store five days before he was found at his Paisley Park estate.
Prince’s brother-in-law Maurice Phillips reportedly claimed the singer had worked for six days without sleep when friends and family held a private service at the compound on Saturday.
Mr Phillips, who is married to Prince’s sister Tyka Nelson, is said to have told fans outside Paisley Park: “He worked 154 hours straight. I was with him just last weekend. He was a good brother-in-law.”
Max Timander, who works at Electric Fetus, said Prince visited a day after the Purple Rain star was rushed to hospital when his plane made an emergency landing in Atlanta, Georgia.
Celebrity news website TMZ reported he had overdosed on a painkiller called Percocet at the time.
Mr Timander said: “Everyone I’ve talked to on that Saturday said he looked kind of pale and he was not totally looking in the best shape as he normally is.
“It sounded like he was looking kind of weak. I know he had just got over the flu supposedly.”
The mayor of Chanhassen, the city which is home to Paisley Park, said discussions were taking place to stage a public service in the Minneapolis area.
Prince was found collapsed in a lift by staff members on Thursday morning, more than 12 hours after he was last seen alive when he was dropped off at Paisley Park.
The 57-year-old singer was pronounced dead at the scene.
Police are investigating whether foul play was involved in Prince’s death after authorities said they had “no reason to believe” he killed himself and there were “no obvious signs of trauma” on his body.
According to Electric Fetus, the six records bought by Prince during his last visit to the store were Talking Book by Stevie Wonder, The Time Has Come by The Chambers Brothers, Hejira by Joni Mitchell, Inspirational Gospel Classics by Swan Silvertones, The Best Of Missing Persons and Santana IV by Santana.