When it comes to being single, masturbation is just fine. You can end it as soon as you want, you can stretch it out as long as you want. You can go slow, fast, rough, softly. You can use toys, you can use your fingers, hell, you can use your pillows! And, at the end of it, you don't need to pay anyone, engage in any awkward conversations (unless you're walked in on I suppose), no need to worry about what the other is thinking, no worries, no problems.
However, if you actually are in a relationship, forget solo action, double team your genitalia!