I bought a pair of T5 lights from Home Depot to put seedlings under when they first emerge. When there is snow on the ground still outside. They were less than $25.00 for each two tube light panel.
I have seedlings growing right now though that started life outside from day one under the sun and they are growing better than any seeds I have started inside. Rain or clouds in warm weather doesn't seem to adversely affect my plants that start life outside from day one. All I am growing outside now are autoflowers. I am above the 45th parallel, just across the lake from Ontario, Canada.
Once your plants are established outside and beginning to flower I learned not to take them inside if possible especially if using a grow tent. You end up bringing pests inside and then they spread to any plants you are growing inside.