Of course, you'll need 4 springs. Here are a few considerations when choosing upgraded 3D printer bedsprings:

Rigidity

The replacement springs are more rigid than the stock springs, increasing consistency between prints and reducing vibration.

Length

The replacement springs are the same length as the original springs, meaning you shouldn't need to adjust your Z-axis endstop like you would with longer springs.

Shape

The replacement springs feature a flat top and bottom (vs. the stock springs' rounded top and bottom), resulting in less spring movement or shifting during and between prints.

tl;dr;

After much research, I found these to be the best Ender 3 bed springs available on Amazon. They're under $10 with free shipping.