Most of the seeds and seedlings sold in stores for us common folks are non-gmo, although a few seed companies source of seeds may come from monsanto. Just a google search away. Planting your own is food stuff basically the best way to ensure that no unwanted chemicals are being added to your food. Wealthier folks may be better off to try ensure their food products are USDA organic (non-gmo) to help encourage farmers and food manufacturers to farm non-gmos.
I am not against GMOs per se, but the way monsanto has been tailoring it around roundup I cannot justify. I Only spotted one honey bee in about 2 weeks in my garden. While I doubt their absence is due to monsanto locally, their absence I find disturbing. Other pollinators are picking up the slack (not that they are required for everything), but I am not sure how many of them could produce honey.