I can get 15 pots of seed in one tray and the depth of the soil seems to enhance good root development of my seedlings. There are all kinds of fancy kits on the market for germinating seeds but these are generally not necessary for good germination. Cardboard egg trays are not the greatest in my experience, even though every garden article ever written on the subject mentions them. They tend to dry out quickly, have pretty small spaces for fast growing roots and can mould if you overwater them. Other than that, they are fine.
Perennials generally require different conditions from annual seeds.
It is this type of seed that will be the focus for the first while. While in our nursery, we divide our seeds into three different categories for germination, the following system will work quite well on the home front with little work. Obtain a good supply of baggies, one for each seed variety being germinated, and some damp but not soggy vermiculite. Vermiculite is perfect for this task, it holds moisture well and it doesn't rot. A permanent magic marker and seeds round out our list.