I start all my herbs, flowers, and vegetables from seed because (1) there’s something magical in that, and (2) I don’t trust commercial seedlings for not having all manner of pests and diseases. Aphids alone can ruin an entire garden.
You can build a hobby greenhouse, but I use grow lights in the cellar. More on that later, but for now you might consider buying a heating mat. Those germination mats are crazy costly, but they never wear out and take little power. I have just one to use for stubborn hard-to-germinate herbs such as rosemary and for peppers. I warm up 72- or 128-cell flats there, so we’ve plenty of room for different varieties, carefully labeled. It’s only for germination, though, so the minute one small crop is up, off it goes into larger cells, and in its place goes more hard-to-germinate seeds.
Some say to use the top of your fridge instead, because it’s warm there, but mine is too full of hats, mittens, old ice trays, and cookie sheets. They’re staying, and that’s my final decision.