Fair enough.
But if you ever just want to go with just the dry flowers, there is always that option.
So did you have a model in mind? Is it going to be in a sauna or in a steam environment? Just a few things to consider. Since $19.99 can get you a lot of things on ebay.
I don't see a reason to buy another unit if a simple solution around the corner is available. I'm sure the EQ is capable and robust for that matter. BUT One big consideration for anybody. Is there is a danger of having oil dripping back into the heater? If any idea is a little unsafe or worry some. Yea go for the $20 solution. Not worth the heartbreak of a dead EQ.
People have used different liquids in the pads and you have a wide range of temperature control to work with. Just haven't covered that area myself.
What would happen if I brushed oil on the inside of my potpourri dish then heated up the EQ and ran the fan? There would be some drip down. If I had a long wand (I do.) and brushed a little towards the top and ran the EQ with a screen in, would that be safe enough to run the fan and fill the room with say the scent of lavender oil? I need to make this place smell like old timey soap.