Donkey Kong 64 Wiki

Cranky will not sell you any potions before completing the training barrels and getting Simian Slam. Even if you perform Funky Weapons Glitch, you'll still have to do that in order to buy upgrades.

Upgrades can only be bought in a specific order, meaning you can't buy later upgrades without having all the previous ones. Also, upgrades need to be unlocked by entering levels. If you get to a level for the first time, you will be able to buy all upgrades from that level and all the previous levels.

DK Isles Jungle Japes Angry Aztec Frantic Factory Gloomy Galleon Fungi Forest Crystal Caves Creepy Castle
potions for all kongs Simian Slam (0) Super Simian Slam (5) Super Duper Simian Slam (7)
DK potions Baboon Blast (3) Strong Kong (5) Gorilla Grab (7)
Diddy potions Chimpy Charge (3) Rocketbarrel Boost (5) Simian Spring (7)
Lanky potions Orangstand (3) Baboon Balloon (5) Orangstand Sprint (7)
Tiny potions Mini Monkey (3) Pony Tail Twirl (5) Monkeyport (7)
Chunky potions Hunky Chunky (3) Primate Punch (5) Gorilla Gone (7)
Funky basic weapon (3) Ammo Belt 1 (3) Homing Ammo (5) Ammo Belt 2 (5) Sniper Sight (7)
Candy instrument (3) Upgrade 1 (5) Third Melon (7) Upgrade 2 (9)