Step 1: Visit Flaticon and find some icons that looks useful to you.
Step 2: Don’t pay for membership, instead, take a screenshot of the icon you want using the windows Snipping Tool.
Step 3: If you haven’t done so already then get Inkscape.
Step 4: Open up Inkscape and start a new project as normal.
Step 5: Drag and drop your previously snipped image into the Inkscape workspace.
Step 6: Go to top menu bar and select Path/Trace Bitmap, try using the settings illustrated here:
Step 7: Hit apply. This will produce a new vector image.
Step 8: Make any adjustments you want to your vector image and then select export using the side menu dialogue. You can also use the top menu with Files/Export.
And there you have all the icons you want from Flaticons (or any similar site) without having to pay.