Even though I have not used the below site extensively, you can try getting your seeds from there. The URL is facebook.com/groups/1497277347217825/
Check Parameswaran who provides open pollinated seeds at a reasonable rates. I don’t vouch for anything but only recommend based on hear-say.
If you want to go for quantity, hybrid are the best options. If you want to grow quality, open pollinated or heirloom variety is the best option as you don’t have to source seeds again as these can be used as the base seeds for your next sowings.
Open pollinated does well with organic methods and the quality of crop fetches good rates in the market compared to hybrid with chemical based farming.