Martin and his friends started brewing beer at home. They started with simple and manual temperature monitoring which appeared to be inconvenient. First of all you need to be in place to check fermentation temperature. So they started looking for simple system that would read temperature and plot data on the web. They found out that most of them are over budget or require significant effort in configuring. So they started their own Brewmonitor.
They took cheap Arduino clone and connected DS18B20 temperature sensor. Then they used ESP8266 Wi-Fi module for internet access. By using POST method they were able to post temperature values to web-server with PHP and MySQL. AngularJS front-end graphs data and refreshed it every time page is loaded. From this point system can be further upgraded by adding freezer/heater to sustain required temperature. But again, additional features may rise overall cost. Keep an eye on project at Git.