I bought this seeds starter at Home Depot. Any local hardware or garden store should have these. They are great because you can moisten only as many dirt packs as you are ready to use.
I keep the tray on the window sill in the basement. You basically want the seeds in a location that is slightly warmer than outside and gets some sunlight. This could be a basement, garage, or indoor window sill.
I like these dirt pods because they have a thin cheesecloth-like layer around the outside. This allows the roots to grow out, but the dirt to stay in, which makes for easy transplantation later in the season.
If you don't want to buy the dirt packs I have a few other ideas for you. In past years I have saved old containers that plants have come in, then started my seeds there. This is green and free! If you do this I would recommend really packing down the potting soil. When you transplant the seedlings into the ground you want the dirt to stay intact so it doesn't rip out the roots.
Toilet paper rolls definitely offer some advantages. Not only are you reusing your trash for good purposes, but the whole roll can be put in the ground when transplanting. This greatly reduces the risk of disrupting the tiny roots and killing the plant. The toilet paper roll eventually disintegrates and the plants grows! The only disadvantage is that they are made of paper. So in a few cases the paper rolls began to mold and disintegrate before I have transplanted the seedlings. They held so much of the water that some of the seeds rotted instead of growing. Whatever container you choose, it feels good to get planting!