You may be able to get a good variety of tomatoes at your local
hardware, farm supply, nursery, Lowe's or Home Depot. My Lowe's carries
Burpee and Ferry-Morse seeds. I don't think I have every had a problem
with either of them. Shipping costs will eat up your seed budget faster
than the seeds do.

Stay away from the Big Box stores, they destroyed the entire New England
tomato crop two years ago by sell late blight infected plants.

Last year I planted from seed and also from several local nurseries, I had
a fantastic crop. A couple of the larger nurseries had a large selection
of unusual varieties which is what I'm looking for. The smaller garden
centers generally don't have a lot of interesting plants, mostly the
modern hybrids like Big Boy, Early Girl and Romas, but if I find an
heirloom there I'll buy it just to spread the wealth around.