I have seen garlic in seed catalogs before but is EXPENSIVE. As in $10 for 1 or 2 bulbs. I just use the stuff from the grocery store. It is said that it is usually sprayed with a chemical that prohibits them sprouting in the store but I usually do not have a problem. I was experimenting this year and using the 3 varieties and soft neck is grown mostly in cooler climates which might be part of my problem. I also use store bought ginger rhizomes and grow enough ginger in pots to usually last a whole year.
I tried ginger in a pot but late in the spring. 1 of 3 plants already died (helped by my dogs who broke it). I hope they will grow back.
about a month ago I bought curcuma rhizomes and I hope they will start sprouting as ginger did so that I can plant them as well.