Terri, I think that a lot of seeds can be started indoors without any heat mat.
IF you're like me, the easiest way to kill seedlings is by over-watering.
Here's what I do to help seedlings survive my over-watering compulsion:
http://garden.org/ideas/view/R...
If your seedling mix holds too much water, it makes over-watering almost unavoidable (for me). So I also "open up" or "loosen" any potting mix I buy by adding coarse amendments (screened pine bark for me, but Perlite or grit help, too. Even coarse sand is too fine to "open up" potting mix.
If you've had bad luck using tiny plastic cells in 1020 trays, maybe consider the "old school" way of starting seedlings: in big flats. Maybe you'll have better luck that way, but you will have to "prick out" the seedlings into Dixie Cups or 3" - 4" pots soon after they emerge (like when they have 1-2 pairs of true leaves, if not sooner).
I consider most perennial seeds MUCH harder to start than most annual seeds. Maybe
practice seed-starting on zinnia or marigold seedlings, or some vigorous vegetable.
Nothing like a tray full of vigorous seedlings that jump right up and then drag their tray out to the garden so they can jump into the soil. If you get in their way they'll elbow you aside to fulfill their destiny. Compared to common vegetables, many perennial flowers are demanding fuss-budgets!
(I tried to start some perennials my second year starting seeds, and got ZERO spouts from 3-4 trays of seeds. And those were 98-cell and 128-cell trays! Over-watering AND no stratification. But I have had SOME Pacific Giant Delphiniums sprout with no stratification, say 20-40% germination rate.)
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They WILL need light as soon as they emerge, so I agree you need a light fixture. (Sunny windows tend to get too hot while the sun shines in, then too cold and drafty at night. Plus you only get enough light from them for a few hours per day.)
I would look for 48" shop light fixtures on sale. One fixtures with two tubes would let you keep two trays of seedlings under good light, or four trays under insufficient light, but you could move them around
Make sure the bargain fixtures DO have light bulbs already, or add that into the total cost to see if the "bargain" was really a bargain.
(Edited to add: Look for a "Habitat for Humanity Restore" for 48" shop lights. Like a Salvation Army thrift shop but with construction stuff. If you check it every few weeks, you have a good chance of finding shop lights eventually. There are also some websites dedicated to local recycling.)