You are supposed to bring your device. If you don’t have one you can get a loan to buy one and pay it off by paycheque deductions.

Once hired, you do get a “laptop refresh bonus” every 3 years, the problem being that it’s a bonus and so is subject to income tax, plus in some jurisdictions you can’t tax deduct computer purchases unless you are self-employed, so the purchasing power of the laptop refresh allowance is basically halved; i always ended up having to top up from my own money to get a decent laptop every 3 years.

Source: former Canonical employee.