You can volunteer and work. I have a full-time job Mon-Fri with a charity, and volunteer (unpaid) at fund-raising events on some weekends. You could also do some evenings, like with cadets, youth club or sports, community work where there isn't a massive commitment or the need to attend regularly, or get involved with the occasional fund-raiser. It's what you find manageable, what you enjoy and gaining some transferable skills.