Seeds are probably second to soil in importance. We know that we get what we sow. If we choose weak seeds of dubious quality, we can not expect a bountiful harvest. Never skimp on seed quality. Planting inferior seeds is not a way to save money.
This time of year, all the big chain stores are putting out seed racks. I have found the quality of these kind of seeds to be questionable. Typically you can find far better quality and selection by mail-order. I like to purchase seeds from a company that also sells to market growers. A grower who is planting vegetables for a living is not going to waste time on seeds of dubious quality. If their seeds don't grow well, they haven't just lost a hobby crop, but a livelihood. If a company continues to offer poor quality seeds, a grower will take his business elsewhere. I also like to look for a company that does their own seed trials so that they can offer the best seeds for their climate zone.
It is probably obvious then that you should choose a mail-order company from your climate zone. Don't buy from a company in the south if you are in the north. You want to find seeds that are bred to do well with your soil and climate.
There are many good seed companies but if you want a few suggestions—try Territorial Seeds if you are in the northwest US, Park Seeds for southern US, and Stokes Seeds or Johnny's Select Seeds for the northeast US and Canada. Of course there are many other excellent seed companies but if you have never ordered seeds, this will give you a place to start.
Another option I have found to be good for seeds is some of the smaller garden centers that offer bulk seeds. The quality of these seeds is usually good, though the selection is not as good as mail order.
If you plan to mail order, do it soon. This is the busy time for seed companies. The sooner you get your order in, the more likely you will get the varieties you want and faster service. My seed order arrived several weeks ago and I was sure that it brought a whiff of spring in the box!
But it snowed the next day. Maybe spring is not here after all.
Where do you like to buy your seeds? Have you been pleased with the quality?