I love going to the farmer's market. I haven't in a long time, but I used to buy raw milk there straight from the farmer.
Why is it called farmers market.Does it mean its exclusive to farmers only?
It is called a farmer's market because consumers can buy products directly from the farmers in a physical retail marketplace.
OK, ,when was the earliest history of such markets?
Forms of marketplaces like this existed before the Industrial age, but were often part of a much broader market where suppliers also bought their goods.
That good.Is it regulated by the government or is it a free and open market operations?
I'm not 100% sure of the details, but due to their nature they do tend to be less rigidly regulated than your typical retail shop for produce. 
So what are the major items of sales at the farmers market?
Farmers' market
A farmers' market is a physical retail marketplace intended to sell foods directly by farmers to consumers. Farmers' markets may be indoors or outdoors and typically consist of booths, tables or stands where farmers sell their homegrown produce, live animals and plants, and sometimes prepared foods and beverages. Farmers' markets exist in many countries worldwide and reflect the local culture and economy. The size of the market may be just a few stalls or it may be as large as several city blocks. Due to their
Entekrishi.com
Entekrishi.com is an online open market for consumers and farmers to connect directly with each other.
Entekrishi.com is a solution of Digital Farmers Foundation(NGO – Reg.No.86/IV/2016) for both the farmers and the consumers in Kerala where farmers can sell their crops directly to the end user without any middle men intervention, thereby getting a guaranteed price for their produce and the consumers can reap the benefits of having organic products which they can personally check at the nearby farmer's field.
History.
The word "entekrishi