From my understanding the only way to get merit is through members or have I seem to be missing something?
You are right. Getting a merit is like courting the woman of your dreams. You need to open up your mind and think outside the box. You need to unleash the creativity and artistic power vested upon you by your ancestors. Mainly focusing on getting merits just to rank up real fast won't get you anywhere. You can't please everyone but with a creative, constructive and valuable post, people that will read your post will be drawn to the merit button graciously like being compelled to do so. Mind over matter in everything that you want in life. Always think positive thoughts and everything will be in line with your plans and expectations. Patience, hard work, effort, time, creativity and knowledge are the key to everything. Not just in acquiring merits but also in improving yourself to become a productive individual with a purpose.
Are there additional ways in which we might receive merit? Maybe by the amount of time we are logged in on the forum, the number of responses we get on our posts despite not getting any merit for it?
Before the merit system was implemented, members will just automatically rank up over time with the number of activities. I kinda love the merit system for it can awaken the creativity and the poet within me.

For example I would give you MERITs if you found cash I lost yesterday.

I totally disagree with you on this. Merits are not meant to be bought, sold or even made as a mode of payment in exchange for some tasks or services.