Other items and supplies include a plastic drip tray motor oil and a container for waste oil. Often a large piece of cardboard is useful as well an old rag or cloth. Also know that this guide deals with push or self-propelled mowers not riding mowers. While some advice here applies they are another animal altogether.
Place a drip pan or other container on the side of the mower with the filler. Carefully tilt the mower so oil drains out and into the pan. Discard the spent oil into a proper disposal vessel. Now slowly pour fresh oil into the mower. For the specific type of oil you need check your instruction manual. Make sure to add only as much as your particular model requires. Remember to let the mower sit undisturbed for a few minutes so the oil settles properly inside the engine.
Top 5 Lawn Mowers recommends the Sun Joe MJ401E to people with a small yard who dont want to spend a lot on a mower. The reviewer liked it overall for many of the same reason one might like any electric mower (no fossil fuels lightweight etc.) but he also noted that there were only three height positions with the lowest scraping the ground. And due to its 14-inch blade it takes longer to mow a lawn.