These days, brand name is not so important. As long as it can measure both AC/DC voltage and Resistance ( aka OHMS ). A decent one can be purchased for $20 and up. For electronics you would want a more expensive one for measuring resistance, but for general purpose any brand will do.
Practice with it and get used to how it operates, all those batteries the everyone has sitting in the kitchen drawer ( AA, C, D 9 V, 12 V Latern Batteries ), are fun to test the remaining power in each. Using the OHMS setting to check continuity on an extension cord ( Make sure it is not plugged into a power outlet), testing stereo speaker wires, you name it, once you are comfortable with it, you'll become a wizard at troubleshooting and testing electrical problems.
You will become popular, women will call you day and night because of your electrical prowess
, ok I digress lol, But don't be surprised if you end up helping a friend or family member with your new found skills.
Just use some common sense when you are working with high voltage ( Household current, Spark Plug wires, TV Components, electric capacitors).
The motorcycle battery should test fully charged at 12.8 VDC or higher. 14 VDC would be too high and a lot of battery chargers will literally cook a battery by overcharging it. They are fine for short charge cycles. A battery maintainer is always a good investment for automotive batteries not being used all the time. Especially motorcycles can sit for days on end and the battery will slowly discharge over time.
Good luck, have fun and feel free to ask any questions.