Kettle for boiling water - not just for tea. Around $25

Microwave - the convenience cannot be overstated. Get one secondhand from a charity shop, look for one with high wattage numbers from a brand you've heard of before. Maybe $50 used

Air freshener - a neighbour will inevitably do something that makes your apartment smell awful. $5-10

Bidet - wash yourself. $30

Better shower head - apartments almost always have crap ones, but they're really easy to swap out. Get one made of metal, spend like $75-100, bring it with you when you move.

Headphones - get ones you can use with your computer, phone, and tv. Your neighbours will thank you for not waking them when you have insomnia. $20-infinity

Hand mixer w/ dough hooks - you're probably going to want to bake something or even make a pizza dough and it's so much nicer than having to do it by hand. Around $30-40

Glass storage containers for food - your leftovers and dry goods will thank you and you'll thank these for not smelling weird in 6 months like Tupperware would. Get ones with silicone seals or pyrex ones with plastic lids. DO NOT MICROWAVE THE LIDS. $20-40 depends on size and shape.

Spoon rest - nothing is more annoying than not having somewhere to put down your spatula while you're at the stove or setting it down quickly only to have to rewash it immediately. $5

Vacuum cleaner - get a used commercial one like an Oreck XL or a taskvac. They're cheaper, lighter, more powerful, use less energy, and are more durable and repairable. The bags are usually cheaper as well. Local vacuum repair shops usually have a few lying around, if not then try ebay. $30-100