if you regard it as equivalent to making your own jam,pies or bread, and are prepared to take time, you can get some lovely results. Very dependant on ambient temperature, base ingredients, and with all the TLC in the world you can still get failures.
The equipment can be fiddly and the demijohns need to sit somewhere warm while they ferment. Then there's the washing and sterilising of wine bottles, and finding suitable corks.
If you are prepared for some not so good and some failures, it's perhaps worth a try. If you want affordable plonk go to a supermarket!