Need laptop for school, price range around $300-800 CAD

You are welcome . Both laptops have same disk drive though, the only difference is of memory which you can extend at purchase or later and the screen technology & resolution, dell has HD and Lenovo has Full HD. I think lenovo is a good option at this price level.

Here are all the best laptops which you can buy in your budget ($300 to $800)

Under $300 - Asus X540LA-SI30205P - https/www.amazon.com/Asus-X540LA-SI30205P-15-6-Inch-Laptop-Windows/dp/B01DMNX5PS/

Specs -
15.6" display HD resolution.
5th Gen Intel CoreTM i3-5020U processor Smart dual-core, four-way processing performance for HD-quality computing
4GB system memory for basic multitasking
1TB hard drive for ample file storage space
Windows 10 Home

Under $400 - Acer Aspire E 15 - https/www.amazon.com/Acer-Aspire-i5-6200U-Windows-E5-574-53QS/dp/B01B9HBP4C/

Specs -
6th Generation Intel Core i5-6200U processor 2.3GHz
4GB DDR3L SDRAM Memory
1TB 5400RPM SATA Hard Drive
15.6-Inch HD Display, Intel HD Graphics 520
Windows 10 Home, Up to 6-hour battery life

Under $500 - Acer Aspire E 15 E5-574G-52QU - https/www.amazon.com/Acer-Aspire-E5-574G-52QU-15-6-inch-Notebook/dp/B019G7VOSO/ (Recommended)

specs -
6th Generation Intel Core i7-6500U processor 2.5GHz
8GB DDR3L SDRAM Memory
1TB 5400RPM SATA Hard Drive
15.6-Inch Full HD Screen, NVIDIA GeForce 940M with 4GB VRAM
Windows 10 Home, Up to 6-hour battery life

Under $600 - HP 15-ay018nr - https/www.amazon.com/HP-15-ay018nr-15-6-Inch-Laptop-Intel/dp/B01GFYP8II/

specs -
15.6-Inch diagonal full HD IPS uwva bright view wled-backlit (1920x1080)
Intel Core i7-6500U, 2.5GHz, dual-core Processor
8 GB DDR3L SDRAM Memory
256 GB M.2 Solid-State Drive, Super Multi DVD burner
Windows 10 home

Under $700 - Acer Aspire E 15 E5-575G-76YK - https/www.amazon.com/Acer-Aspire-NVIDIA-Windows-E5-575G-76YK/dp/B01F1Z78GM/ (Best value option)

specs -

6th Generation Intel Core i7-6500U Processor (Up to 3.1GHz)
15.6-inch Full HD Display, NVIDIA GeForce 940MX with 2GB DDR5 VRAM
8GB DDR4 Memory, 256GB SSD
Windows 10 Home
Up to 12-hours Battery Life

Under $800 - ASUS K501UX - https/www.amazon.com/dp/B0146DD02G/

specs -
Powerful 6th-generation Intel Core i7-6500U 2.5GHz (Turbo up to 3.1GHz). Skylake
15.6 inches Matte FHD display. 1920 by 1080 resolution. Windows 10 Operation System.
NVIDIA GeForce GTX 950M gaming graphic card; 8GB RAM; 256GB SSD Storage. Backlit keyboard.
Gigabit Dual-Band 802.11AC ultra-fast Wi-Fi.
Feature 2 x USB 3.0, 2 x USB 2.0, 1 x HDMI. Bluetooth 4.0.
1 year International Warranty with 1 year Accidental Damage Protection

Source - https/laptopunderbudget.com/best-laptops-for-college-students/

Shoulda probably mentioned you were in Canada a little sooner.

Many direct vendors provide the service to extend the components while purchasing the laptop. You can contact their customer support. I would suggest you to contact their customer support first on the website It would ensure extended memory issue before you actually buy.